This is a question from a Bjornaer player in our Saga last night. The discussion we had centred on the fact that the Parma guidelines insist on the recipient's 'consent' to have Parma extended around them. I determined that a norm 'dumb' bear was unable to comprehend the situation and could not offer consent. He argued that with his character's novel linguistic and animal related skills (think Dr Dolittle) he could persuade the Bear it was a good thing to do. Thoughts most welcome (and a strong cup of coffee!).
I can't offhand think of a way it can be abused (well, abused further than extending PM to other humans anyway!),
I would have no objections - the "consent" could be implied for any character who does not activly wish to be subject to PM. It becomes a little trickier if recipients are expected to do anything during the PM ritual, but any character with animal ken or other "speak to the animals" abilities should be able to either talk them into it, or if given time, train them to participate(as in RoP:M),
I don't think 'consent' requires the consenter to understand all the ramifications of what he is consenting to (it's not like you would explain to a random mortal how Parma Magica works exactly, beyond "it protects from magic"). In my opinion, agreeing to put himself under the protection of the Bjornaer is consent enough to receive the Parma Magica, and most animals should be capable of that much.
Nobles' Parma on the exact page reference, but the Tremere chapter of HoH: TL refers to the need to extend Parma to steeds as one of the reasons for House Tremere preference for infantry over cavalry...
I'd still say the consent is needed, but consent for an animal would be a judgment call. I'd say it's much akin to how much the animal trusts the caster. If the animal trusts you, I'd say it'd consent. If an animal was cowed by way of magic, that'd also provide consent. If it isn't sure, then some kind of die roll or roleplaying moment might be necessary.
Just the way I would rule IMS... YMMV.
Of course parma can be extended to an animal. An animal is a "character".
As to consent: sure, an animal can give consent. A horse can consent to being ridden, a cow can consent to being milked, a cat can consent to being patted, etc. Of course, it's a judgment call as to whether an animal has given consent in any particular situation. For an animal, "not consenting" pretty much boils down to either "running away" or "attacking". So if it is not doing one of those things, it is consenting.
I would say it would be pretty easy for a Bjornaer (in animal form) to get consent from other animals within (or near to) his linguistic group (see HOH:MC for animal linguistic groups). However, it might be difficult for, say, a wolf Bjornaer to get consent from a lamb. On the other hand, it might be easier for a wolf to get consent from a lamb if both are being attacked by some sort of demon. It would depend on the context.
For people (including Bjornaer in human form) getting consent from animals should be something to do with Animal Handling, possibly modulated by the use of Animal Ken or spells. Again it might be easier or harder depending on the exact circumstances.
Although remember about the effect of The Gift too. Bjornaer in animal form still have The Gift --- so probably come across as quite weird/untrustworthy to other animals.