This is pretty much a non issue. If someone wants a run in progress they will get a run in progress making you wait longer regardless of what the penalty is. Blizzard and the same problem with tanks queuing up for dungeons then hitting cancel when a run in progress didn't pop up. So they stopped showing people if a run was in progress or not. This lead to more tanks leaving a zone right at the start because they didn't get what they wanted they rather take the 30 min cool down and do something else then do a whole dungeon.