My husband thinks our large GSD should not play with tennis balls because one could get lodged in his throat and suffocate him. Is there any truth to this? Otto loves chasing and retrieving them; it's an important part of his day. I'd hate to give it up. He doesn't catch them in mid-air, only scoops them up off the ground. I don't see the problem myself but I promised him I'd ask for other opinions.