I've been able to "train" all my tree frogs to eat from a bowl. You should be able to do the same thing, if you wish. I prefer that method, less escaped crickets, no chance of them scooping up moss, substrate, or anything else they shouldn't, and I can see EXACTLY how much they're eating. It shouldn't be a problem if they die so long as you have microfauna such as springs and isos though.