June Bugs, june beetles, junikäfer

anyone have experience with these guys? en.wikipedia.org/wiki/Amphimallon_solstitiale
From what it looks like my upstairs neighbor, who has a roof terrace has a mild infestation of them... thankfully, she has more plants than I do, but any ideas on dealing witht them?

I just let them fly. They do no serieus above-ground harm, and I have yet to find the first grubs in my pots. Leave the birds some food.

I didn't think they would be much of a problem in Bonsai soil, or bonsai type soil, plus they seemed more interested in my neighbor's terrace than my balcony.