Ive seen like 6. I can recall the last one I have seen. Most of official squad members were in game, not even afk, but It was clear that they didn't even want to try to join the free-for-all fight. So I agree with the guy above. Those occur quite often these days but 4 cops coming there 1 by 1 have got no chance against 20 criminals protecting each other. You can manage to arrest one but till you get another, the guy you had arrested gets released.
This is as old as the hills that squad members beg for being armored due to lack of active members on, but I dont really agree this is a good sollution. I've heard someone asking for grenades to be disabled at all, I dont know If that is possible, but grenades disabled in turf zones would probably level the playing field.