Personally, I think there's responsibility on both sides. Yes, you should have left out the DND sign and locked the flip lock, but they should have knocked and waited for a response before coming in. I don't think just because it was 10 am that they should have some sort of pass from knocking or expectation that people might still be asleep. Outside of Disney, if I stay at a hotel more than one night, I'm bound to sleep until noon. Even on check out day, I'll sleep until 1045.
It doesn't sound like anything was done maliciously and it seems it was an honest mistake, so I wouldn't push for anything big. I would definitely have had a chat with the manager about how nobody should be going into rooms without knocking. If I was in your shoes, I would have liked more than $10, not because I felt my inconvenience was worth some arbitrary dollar amount, but because on the hotel's behalf (any business' behalf), it's the nice thing to do when they make a mistake. I wouldn't ask for anything though or demand more, because it wouldn't mean as much if it felt like I had to force them for it. A free meal voucher or something along those lines would have been nice, but again, if they didn't offer it, I wouldn't push. I would just let my displeasure with the situation known, and I probably would hesitate to return there.
In regards to the door locks- I'm young still, so please don't flame me! It was only a few years ago that I learned that you should flip the switch lock thing to keep hotel personnel out. Every hotel I've stayed at has had a deadbolt kind of lock and I had thought that would prevent any random housekeeper from entering your room and that the other switch lock was more of a convenience to keep young kids from escaping out of rooms and to be able to open the door just a crack if you weren't sure you wanted to invite someone in. I have of course since learned that the deadbolt lock does NOT keep hotel personnel out and I do always flip the top switch. I've been to several hotels over the years though that didn't have DND signs. Regardless, there is some responsibility on people to use the lock and sign, but as hotel guests, I think we all still have the right to the respect of a knock on the door before someone enters or even attempts. Signs aren't always there to put out and sometimes fall down and if someone goes for breakfast while others are asleep in the room, the switch can't be flipped. Guests should always be given the courtesy of a knock before someone comes into the space they have paid for.
It happened to us a few weeks ago and I'm sure it's happened before. I actually felt a little bad that we were holding up their process and since it was getting close to check-out, we just hustled-up and got going. It never once even occurred to me to report it to management. I think I'll contact them now and ask for $10 bucks! ($13.21 CAD). 
