Hi Elliot
That would certainly be something I would consider doing if I was in your position. Fortunately, there is still a minority using waterfed poles and you'd would be surprised how many customers still don't know about it!
Customers also share the risk of insurance claims if a contractor has an accident on their premises so it's in their interest to minimise the risk.
Maybe you could do a promotion like you'll clean the frames for free on their first clean (you'll probably do it anyway)
Regards
Mike