Upset Recovery training is NOT airshow flying. It is not done anywhere near the ground. Accidental collision with the ground is not on the radar!
Upset Recovery training is NOT competition aerobatics. There is no reason to stress the aircraft to near its certified G limits. Structural failure is not at all likely.
What about mid air collision? We do reverse direction rapidly and climb and descend a lot. A good instructor will constantly and seriously clear the area. He should always avail him or herself of radar flight following. If these are done midair is probably less likely than in most other general aviation flying where clearing is often done in a cursory fashion if at all.
What about the risk of fire as we put stress on tanks, lines and fittings? We wear chutes. We do not have to stay with a burning aircraft to landing. We seriously train aircraft egress and the use of chutes. A decent Upset Recovery instructor simply must do that!
All in all Upset Recovery training is probably safer than what you normally do in your aircraft!