If you haven't had any problems ,why do it all the time????? There is only one GUARANTEED prevention. That's Miller's Trophy Room. You can bag it and bomb it, fumigations and foggers, heck cross your fingers but even professional fumigators won't guarantee it. How you handle your customers is your concern, but I refuse to let anyone that asks be told a way that won't cut it. I would rather not answer then give a wrong answer. I tell my customers Miller's, some refuse it and soem see the benefit. If they refuse, I note it on my paperwork. Somewhere down the road if they have a problem they can't blame me.