Ummm, why does the OP allow this?? Are you unable to man-up and just say "look, we have some used balls here and some new balls here, we're going to use the new ones. My treat." HE doesn't like the brand you bring?? Oh. Well you don't like what he brings! If you were sharpfox instead of slowfox, you'd just bring a brand that's okay with him, as then he'll have no excuse at all for not playing with new balls.