Camarilla
Let's say, you are an open Camarilla member actually sent by Sabbat. The odds are very high that you are Blood Bound to someone, maybe mutually, maybe not (after all, that's what Camarilla is infamous for). This will make it a hard decision to give info to Camarilla enemies. After all, you understand that it may get killed those who you are bound to. If bound to noone, that may look very suspicious. I can imagine such a character being a spy, but not really for long, he would get caught in a single chapter, and recruiting more spies would be very hard because of that.
I thought about participating in Vaulderie as a possible way to fight the Blood Bond, but it is a risky practice. If a spy cell is present, it may be easier to hide the Vaulderie, but if one cell member is caught... And not even mentioning having to go outside to take Vaulderie, it's suicidal.
Sabbat
Now let's say that you are with Sabbat officially, but try to spy for the Camarilla. You have to participate in Vaulderie frequently, which ruins any existing Blood Bonds, and makes you interconnected with more and more Sabbat members. Once in a while, you will simply be unable to take any actions against the Sabbat, at least the part you are infiltrating, and are likely to become a real Sabbat member. If you don't participate in a Vaulderie and actively avoid it, you will live a very short and unhappy unlife.
Both sects
Of course, Madness Network or SchreckNet could do the job, but they are both limited and as far as I know info gained this way is normally not fully shared with the Sect.
So, what am I asking about:
- Canon examples of spies (and by "spy" I actually mean a mole or a sleeper agent) from any canon books, which also tell how did they fight supernatural ways to control them (Blood Bond, Vinculum).
- Mechanics that would allow to avoid mentioned restrictions and be a successful spy.
I am not interested in a complete list, it would be too big, though the more examples I get, the clearer things become.