http://warlight.net/Forum/Thread?ThreadID=3652 (See reply by Fizzer in that topic, that's all that I know.)
EDIT: some other old topics in which the same question was discussed:
http://warlight.net/Forum/Thread?ThreadID=6239http://warlight.net/Forum/Thread?ThreadID=1752http://warlight.net/Forum/Thread?ThreadID=5761http://warlight.net/Forum/Thread?ThreadID=22191I don't believe the "hour" piggy is talking about, is necessarily correct. It is certain that someone who returns from vacation, can only be booted one hour later, so it may be related. Either way, based on what Gnuffone and Fizzer say, it's certainly several minutes (but you could be unlucky, see the hedja topic).
Edited 11/14/2014 12:42:47