I'd love it if they fixed this glitch, to be frank it's one of the most annoying. I've been in several parties where half or more of the party will climb up there and try to snipe the tunnel and street nearby while the rest of the party runs around below playing worm on hook. This may make the level a lot easier, but it takes away from the realism and enjoyment.
Definately my favorite is when someone goes to trader before everyone else, then decides they want to get up on the gate. I actually had one person keep opening and closing the gate trying to get up and he managed to block me for around ten seconds from getting to merchant, from the church so on top of being pressed for time I had him to deal with him.
One more favorite was half my group climbing up there then getting stuck off level. They had to suicide to get back in the level and I ended up giving them cash to restock. I had enough to do so because they stayed that way the entire wave, so I and one other guy had to clear the wave alone.