Incidentally, one of the age-old questions of BFSSFG has been settled!

Ex-forum member ella has (access to) a track tandem here in Bp and a couple of friends of hers rode it on the streets... sped up too much... tried to skid to stop in time... turned the front wheel too far accidentally when the skid didn't really happen... and flipped the damn thing!

So there you have it: you can flip a tandem