2 min at PVP is more than enough, that's too much based on how many time each PVP mach take to finish. 30 secs of inativity for auto-kick would fit perfect, this is not a PVE, people are not going to wait you back to fight against each other just like we do at PVE content, your inativity is going to prejudice all Alliances of your GC and do you want more time to be AFK than 2 min?. If you don't like it just use the Bathroom before any registration.