Better than going to full power, jumping the chocks (NO wheel pant to hide them) and chopping up the cone placed to mark the next airplane's wingtip. True story. Guy just had a blank stare and kept taxiing.
This wasn't a Bonanza by any chance was it? We had a guy do just what you described, taxi for take-off, took off and after he got 50 feet in the air decided he should abort and check for damage. Problem is though he aborted he didn't put the gear back down.
Surprise surprise this guy is a Doctor.
http://photos-d.ak.fbcdn.net/photos-ak-sf2p/v648/28/46/1342828014/n1342828014_350206_224317.jpgAnyway, maybe the mirror is to make sure the gear is down prior to landing
