This is what happens in my experience too. At session zero we might throw out some ideas for an adventuring party but before we can come to an agreement people just start whipping out dice and start making random PCs, and then I get inundated with 10 questions at the same time and 5 people trying to all get an answer. This happens at least every five minutes. It's really annoying.
This is really aggravating as well because there's no comradery and in the end we end up with a group that has no realistic reason to even be adventuring together. I've also found that this leads to players not really caring if their PCs live or die because...kill off Bob 1 and replace with Bob 2, insert into party, no questions asked. Hell I've had players just erase the name on their last PC and write in a new one, OK I'm back.