Well accidents do happen in gymnastics ad a lot of them are here for you to see. If you have heart problems don't look.
I will share here my personal experiences as an amateur 'Weekend Stretcher'! I do stretching and my body feels great. I started not long ago but one can tell. And workouts with prior proper stretching are child play!

A referee that virtually sabotaged one team during the entire match got a player to crack and choke him on the field!