Wouldn’t one typically encounter feedback or be more likely
to if the speakers are behind the mic’s? From experience once the mic is aimed in the general direction of a speaker is when I’ve always encountered issues in the past be it rehearsals or gigs. I recall going to play a gig (local bands as a teenager) and the guys had set the speakers up at the back of the stage so “everyone in the band could hear the singer” and our first job was to move them. The other band said it would be fine, plugged in the mic’s and it howled like a a Hammer Horror!