There are lower magnitude spells that can be used.
I was thinking that each Covenant could invest in an enchanted device
that all Magi could use ,
rather than individual spell-casting.
Perhaps - but that would still require that said magi invest in such an device - and that said magi bothered to used it for every item. (and often too - since it wouldn't take long for the items to become AC once more...)
I know the magi at our covenant would never bother with it... (And if one of them volunteered to make one, it would probably be used to gather AC for said magus... Or suspected of doing this...).
An interesting device... Maybe it could simply be installed at the gate? Would easily be circumvented, but still usefull for making it harder to slip out an AC.
Would be a nightmare to anyone with the "Leap of Homecoming" - remember, it breaks any AC - including fixed ones... Do this to a visiting magus, and he'll have you up on charges for breaking the code (preventing his use of magic)
I do not see why - it is only effective on the things brought throught the door.
That is what forceless casting is all about. Or the device could have an build-in way of turning it off temporarily.
And even so it would make a poor tribunal case at best.
A visitor with a AC to his home covenant (for use with LoH) would have said AC broken...
Poor case? Since it takes a seasons work to fix an AC, and it may take another season to travel by foot the distance home, I'd say it may make a damn good case...
As for the forceless casting - that wouldn't matter if the AC was in the bags of one of the grogs (packs on the mule or whatever). And it wouldn't help a redcap either...
Turning it off to prevent this kinda bypasses the whole point. Sure it wouldn't do anything wrong if it was turned off - but then, when do you keep it active, and when do you turn it off?
If used as a Gate or Portal ,
the Magi of the Covenant can come up with alternatives
that do not rely on unsuspecting passersby walking through it.
If it is built without any Penetration levels , it is unlikely to affect Magi.
It does not dispell any magical devices.
Visiting Redcaps are not made to walk through it , and are warned against doing so.
Any visiting Magi , not known by the Covenant , or who turn up unannounced would be treated with suspicion.
They are asked to declare all items on their persons before entering.
InVi spells can determine what items are.
(no visitors with BoAF blasters free to wander around)
The placement of items with AC to other places or leaving with an AC to the Covenant or anyone in it is minimised.
Still removes fixed ACs...
Takes a season in the lab to determine what an item does - InVi will only tell you that the item is magical...
I was not trying to determine what an item did , so much as that it was magical.
Magnitude of effect in a device can be determined , even if not the actual effect.
from InVi Guidelines page 158.
Since you mentioned not permitting people running around with ABoF devices, I imagined that you wanted to know what they did... 
For the truly cautious (paranoid) I still think you need to develope a way to locate ACs to yourself and find a way to destroy them.
Can such spells affect an Arcane Connection in someone's pocket or does the magic item require some way to sense in the pocket?
Well , i did mention concerns about strange Magi who are unknown to the Covenant
and turn up without documents of introduction (or similar plausible means).
The BoAF thing was more a guess as to what you don't want people carrying around.
I figure anything with high enough penetration to work inside the Aegis might be dangerous.
(thus the detection of magnitude)
This is in the realms of speculation , as was pointed out ,
that not all Magi would be this overcautious.
The discussion about Wizard's War on the Berklist was probably giving me flashbacks to the Paranoia Game.
Ohh - this does bring up the second problem of such an item - designing it in such a way that it actually works...
Might be possible to design the gate as a room of sorts, and having it trigger constantly (unlimited no of uses/day, triggered all the time).
Would make the item very high level...
Maybe an item that only reduces the duration of ACs by a single step? That is enough to make many ACs useless, while it would have no effect on fixed ones...
Ok, I'm changing the subject but it related sort of.
The wife is already thinking about Valentines day and she said she was very interested in this:
When she asked me what I thought I said:
"You could do a lot of damage with that!"
When she asked me what I meant I said:
"Never mind."
Hmm, the problem is I can't send one to Abe.... He needs to send it back to me.
Serf' Parma, but IIRC you HAVE to KNOW what AC you are breaking...
IE I am going to break the AC on this letter...You can't cast in on yourself or in an area....
You guys are so funny. LOL.
Already clarifying the rules and plotting it's use on Abe!
Ah, tis the season!
The letter written by the Magus as an AC , must surely have cropped up in the history of the OoH before 1220.
An easy Magic Theory roll would remind you of the actual AC.
In standard Redcap delivery , mail probably takes long enough to deliver that the AC fades.
It would not be hard to degauss all personal correspondence though.