Lest the idea stay tucked away in a thread about something else...

Seems like the best next thing. The only drawback I've seen - at the ferry between Portland, ME, and Yarmouth, NS - is once one dog hits on one thing, she stops and sits or gets excited about it, while another thing gets by. But the solution, lots of dogs, works for me. (These dogs aren't attack or protection dogs. Those are wholely separate breeds and training plans. Think Beagle or Golden. To these, an explosive is almost as good as a ball.)