Simply put your "do not disturb" sign on the door when you FIRST arrive and only remove it on the days you WANT them to come into your villa. Works for us. I don't like being surprised either and truly enjoy NOT having maid service. We know how to clean up after ourselves and keep the place tidy just like at home.
Obviously, it's not that "simple", judging by the posts here. It's not like their criteria is to clean rooms without the sign, and not to clean a room with the sign.
I "know how" to clean up after myself too.

Housekeeping services aren't about tidying up...to me, tidying up implies not having stuff strewn around, and it's not their job to tidy up people's stuff. It's the cleaning. I have cleaning wipes for light cleaning of the counters and sinks, but I've yet to bring a toilet bowl brush on a vacation (and to be honest, I don't want to clean toilets on vacation...so there!

). I also DO want my bedding changed at least once on a 9 night stay. I wash towels along with my other whites constantly with
DVC, but I choose not to strip down the beds, wash the bedding, and then make up the beds again, especially when
what I WANT and SHOULD GET is better service from a timeshare that I'm paying good money for. It just seems like it shouldn't be that difficult to get it right. Especially with computers, and with Disney in many other ways functioning like a well-oiled machine.
Maybe next trip, I'll just harass them daily with phone calls.

"Today I don't want TT or a full cleaning..." or "Today I want..." I guess on the "Do not clean days...", the "Do Not Disturb" sign will work (or so one would think), but we never had one; I did mention it to the young woman at the front desk, who said I needed to get one from Housekeeping, and I just didn't get around to calling them about THAT. (Funny...I thought several visits to the front desk and phone calls to Housekeeping would solve the problem.

) We used the 2nd bedroom's one day, but I have my doubts that using it on the 1 bedroom door would have kept them out of the 2nd bedroom if that was the day they arbitrarily decided to come.