It's much harder to parkour with people afk everywhere. And when you're helping someone or being helped you can't really use /hide. So why not have afk people kicked after a certain amount of time, such as 5 or 10 minutes (5 would be preferred)? It'd cut back on some lag from too many players, and it would prevent spamming complaints.
Good idea. There is really no harm in doing this, as when a player gets back they will be right where they were before they got kicked.
Definete support! I hate it when people afk on track. Especially when they have their pets with them. .-.