well...I guess making a dog run to earn money for the owner or something..and doing it all the time is kinda cruel. But if the dog enjoys it, I say go ahead and do it. Have you ever seen those dog shows on discovery (i think it's discovery..). They often have besenji's, afghans, whippets and italiangreyhounds chasing a lure...they seem to enjoy it...so I think it's alright.