When I am working on the bike and need to have it idle I'm careful of this issue. It gets hot, I don't have a fan available, but it seems to do just fine. I probably don't idle the bike more than 4 mins in these situations.
I've had a couple of times in traffic though that were disconcerting. In the city I have been able to take a different route but several times stuck on some Highway the bike did seem to be too hot. I've adopted the attitude more recently that I have to use the breakdown lane and I either go to the nearest exit or if I know what roads are around I select an exit near by.
The bike runs very poorly when it gets this hot but apparently it's not been a lasting issue as it seems to recover. There have been recent threads about riders that have warped heads or valve covers and these could be from such over heating episodes.