So this came up because for some strange reason, the non-Verditius (Flambeau) mage in our covenant has decided to try his hand at magic items and was casting out (pun intended) for the spell levels via email. (It's ironic that he wants to do this, the covenant has 2 V's and all!)
Anyway, he wants to control his horse so it does not fright in the middle of battle or tournaments. We're set in Normandy so the Tournament is a big deal (we're on our second Tribunal meeting now). Last time such things as mechanical fire breathing dragons (damn automatons) ruined our chances of further advancing in the tourney, so we're all looking for remedies so as to not lose what we last earned of the tribunal vis allotment. The player was sort of basing his calculations from scratch, starting from base L2 (plant a suggestion in animal mind) in order to do this. Of course, there's already a spell specifically for calming a beast, which base L10 "Make an animal passive" (The Gentle Beast) and the GM is pretty much in agreement that you can't accomplish much with "suggestion" if there's a much higher spell which is the better working of it (and even Gentle Beast can be dispelled if going into combat, the horse is badly frightened, or injured, according to the spell description).
That's all background. The real interesting conundrum came as a side effect of looking for similar Base L2 effects that are listed in the book - namely, the Disguise of the Putrid Aroma and Circle of Beast Warding, both L5.
Disguise has the similar caveat in it that the target animal "takes no interest in you...[if you] do not threaten it." In other words, changing the circumstances on the animal (threatening it) breaks the effect, as it does in the L25 Gentle Beast spell, where "if the animal enters combat, is extremely frightened, or incurs any kind of wound" the spell ends. Presumably, a war horse trained in combat (such as the horses the covenant raises) might get some sort of better fright check but even war horses sometimes balk, shy, or run the hell away from total mind numbing enemies. Like fire breathing mechanical beasts...
But Circle of Beast Warding has no such caveat. Obviously it's based on the Base 2 description, "Protect target from animal attacks" but...It's merely a L5 spell, and one would assume that a magus sleeping in such a circle under normal circumstances would be quite safe (the circle "suggests" that the animal go elsewhere), but what about abnormal changes in circumstance, as in the other spells? For instance, what if you, inside the circle, were torturing a bear cub, and the mama bear was outside the circle? Or else you are in a wood in deep winter, and a very starved wolf comes on you, one which will die soon if it does not find food. One would think the circle would be overcome. If L2 "suggestion" can be overcome, and even base L10 "Make completely passive" can be overcome, with circumstances, then how come "protect from attacks" at base L2 can't be overcome? In unusual circumstances?
Now, hopefully this is moot for most, as I don't condone torturing baby animals in the name of finding spell limits, and you'd be pretty crazy to camp out in the middle of winter where there are starving beasts with naught but a probably-spont'ed L5 spell, but it makes one wonder...why the spell limits for similarly-based spells, and even much larger-based spells, but the L5 ward against animals is all powerful?
That would make Circle of Beast Warding, in some respects, more powerful than the L25 spell, or the similarly-created L5 Disguise spell. I think this poses a neat question about the limits of the rules and spell bases in the ReAn section of the Core book. Which is correct...an all powerful Ward spell at L5 (base 2) "Protect target" descriptor, or a breakable L5 (base 2) "suggestion not to bother with me" spell?
(And yes...I'm one of the people playing the Verditii in this campaign...why do you ask??)