I'm decidely mixed on a policy like this. I have been on both sides of this issue. As I mentioned in an earlier post, the Ritz walked in on me for turndown service at around 830pm despite having the Do not disturb sign out. They woke me up and then called later to see why I had declined the turn down service. They woke me up twice with the sign out. I was compensated, but did not stay at that property again.
Next experience was at the Le Meridien in Egypt. My wife and I were in the bathroom getting ready for a day tour of the pyramids. The bathroom door malfunctioned and would not open. It was closed and not locked, but it was not opening. We were locked in the bathroom. I looked around for the house phone to call downstairs. No phone in the bathroom. Unfortunately, on this one occasion, the place appeared to be pretty soundproof. Fortunately, there werent too many places to charge my cell phone and it was in the bathroom with us. I called downstairs. I had both the do not disturb sign up and the deadbolt on. They had to remove the front door, which they took off the hinges very quickly, I'm not sure why a master key card wouldn't open it. Iit was a good 30 minutes more before they could extricate us from the bathroom as the hinges to the bathroom door were on the inside and I had no tools.
I now believe it is a good policy to check on guests daily for their own safety. It would need to be done in the least obtrusive manner possible, but stuff happens.