When I had food leftover once (at BWV), I asked the housekeeper the day we were leaving if I could leave some unopened things for them. She said the housekeeping manager would come in and take an inventory of the items, then it would be known it wasn't stolen from us. They would then take it and distribute it to whomever wanted the items (we had unopened yogurts, drinks and a few other things).
In another country once (Mexico), we stayed at a very high end resort. At the end of our stay, we had dollar store floaty rings and some unopened soy milks in our room (I had brought from home, as DS is very milk allergic). The bellman was VERY appreciative to take everything! I think there, although it was a very expensive resort, the employees make and have very little, so he was so happy to take anything I gave him.
I do think it would be nice if you talk to a housekeeper early in your trip, and explain that when you leave, you may have some clothing that you don't need, and would anyone like to keep it. Definitely talk to them ahead of time. I am sure they could maybe find someone with a child the same size that may want the items. Kids outgrow things so fast! I know I always loved hand me downs from family and friends.
I have heard of many families who take items with the intention of giving them to hotel employees in other countries, like Mexico and the Caribbean, so maybe in this economy, I would definitely think they could find someone who wants the clothes.
Even on our
Disney cruise, I had some things that I didn't need, and my cabin attendant was happy to take them. She was so sweet.