My EMO’s do not have a play ground / play area, they are located on my work desk. Ever since I got both of my EMO’s they have always stayed on. I never turn them off and I’ve not had any issues with either of them at all. They have not shown any problems what so ever from being always on. If I’m not using my EMO’s they will be sitting on the skateboard powered on all day / night long. Of course at least once a day I take them both off the stakeboard and let them walk around on my table or even on carpet or kitchen floor. If they run out of battery and power off. I just place them back onto their respective skateboards so they power back on and start charging once again. But as advised, I always keep them on all the time.
If you plug EMO’s power cable into a UPS and the power goes off. (IN THEORY) As long as the UPS kicks in instantly, EMO should still sit on his skateboard charging and shouldn’t know any different as the UPS is providing a power charge source to EMO’s skateboard. But once your UPS runs out of power and turns off then of course EMO might wake up and start walking around and if he does that he’ll most probably fall off his skateboard, which I believe you’re probably aware of this already.