Not according to what I've been hearing as of late -- or even before 9/11. Avoiding mosques (period) -- especially the handful of infamous ones -- has been the way of Al-Qaeda when it comes to its general approach for more or less direct recruitment. And it's not like the latest Al-Qaeda recruits are even necessarily religious fundamentalists -- a lot of them are anything but. (Remember your disbelief that various white supremacists were looking to hook up with Al-Qaeda and the type? It's still going on. )

A lot of governments are wasting a lot of resources at mosques. That's not where the problems start, can be trailed (generally) or even be resolved. It leads to a lot of false leads, entrapment situations that are nothing but a paid informant trying to keep themselves on the payroll doing no real work, and bigger haystacks in which to lose the same handful of needles.