Actually, I have a few times with my action replay where I've dropped it and froze the game. I've had to restart fro my last save which can be a pain if you don't save periodically like me. I've actually damaged my DSi XL from the constant drops it's had with the AR. It still plays, but it has trouble reading games sometimes. However, after blowing into the cartridge base and cartridge itself, it'll play just fine. After I got my 3DS XL, I gave my DSi XL to my aunt because she's kind of poor and doesn't have stuff like that. Too bad my mom cut her off from being her sister. :[
On other occasions, I've fallen asleep while playing and woken up to a dead battery.