i would definitely be weary of people i didn't know before hand but i definitely think that if your group is 50, 100, 150 strong then most looters would stay away from you unless they were looking for a war, i would try and judge the character of the person and if they had supply's and were trained, level headed, i would probably take them in, there is strength in numbers, i would probably whole up in a home depot or a walmart and fortify that place, i already have a couple of AK's and AR's, and plenty of ammo for each, and i have lots of close friends with assault weapons and military/police training, we could take care of groups substantially bigger than ours just because of skill level, numbers arent everything, i guess theres something to be said for both arguments, but hey, why not merge with other groups? with that much man power you could do pretty much anything you wanted to.