We don't use housekeeping either. We learned the hard way to make sure and put our DND sign out as soon as we enter the room the first time. We forgot once, and even though we had told them at check in and called and told housekeeping not to clean our room, they cleaned our room. The problem was that they took my towels and washcloths--we never use resort towels. The gross part was that the mousekeeper started digging through all the dirty linen in the cart looking for my towels. I told her that she didn't have to worry about it that I didn't want them back. She handled all those dirty towels and sheets and then proceeded to grab the clean towels, wash cloths and sheets for the next room. Yuk. She also picked up the paper cups--they aren't covered in any way- with those same dirty hands and put them in another room.
We also make sure and tell the mousekeeper for the day that we do not want service. I always ask how many days that person will be doing our section so that I know when to look for a new person to tell him/her not to clean our room.
I explain to them it's a health issue so as not to offend them. I make sure and give a tip to each person who would have been cleaning our room. It's sounds like a lot of trouble, but it isn't. They will hang a bag of shampoo, tp etc on our door every day.
For those who are about to say something like, "You're going to be in a park with 1,000's of people. Why worry about your room?" For those people, being in the open and being able to wash my hands diligently, is different than taking a washcloth or towel with no telling what on it and using it on my face or being in an enclosed room where the previous family was sick with the flu, virus etc. or where the mousekeeper was ill and touching everything in the room and coughing etc. is very different. I completely disinfect the room before I unpack the car. I usually come to the room, open the door and spray Lysol or such, and then leave for a while to let it take effect and settle down. Then, I come back and disinfect the room. I had cancer with extensive chemo leaving me with a weak immune system, therefore, I am overly cautious. This has kept me well through several years of Disney trips, while friends that went with us, who didn't bother to clean, ended up getting sick doing exactly the same things we did during the trip. We have been lucky in that they didn't get sick until close to the end of our trips together.