We've tried a lot of different solutions and this one is the best. I wish the "lock" was a little harder to defeat -- would prefer a code. My 3 year old figured it out and has changed the time already.
This is a fantastic chess set for the money. Anyone saying otherwise is plum crazy. I threw out the checkers pieces (don't play it and aren't magnetic) and also ended up ordering a 2nd set so we had backup pieces for when stuff gets lost. It's a great set and once you've played on a magnetic set, you won't want to play on anything else (except perhaps a very fancy and heavy set).