This really depends on the details. If, say, one member of a mosque is under surveillance for good reasons and then you extend that to everyone attending the m

This really depends on the details. If, say, one member of a mosque is under surveillance for good reasons and then you extend that to everyone attending the mosque for no particular reason other than "well, maybe we'll catch something, doesn't to try": that's probably not a good thing. On the other hand, if the imam is preaching violent rhetoric, multiple members are under surveillance for good reasons, and there's good reasons to believe that the violence is an important part of the mosque community in the first place (rather than a relatively small detail): then that's perhaps not such a bad thing. You don't "accidentally" associate with that kind of thing. Or: you probably don't need detailed reasons to put someone in Don Corleone's employ under surveillance.