When we went this December we were disappointed that we couldn't book Crystal Palace for birthday lunch like we have for 6 years so far...
We couldn't book it for dinner or lunch for any of the days of our trip...

Luckily we walked right in without a reservation... we thought we would just check...just in case...usually with a reservation, we have to wait for 15 minutes... but this time without a reservation, we walked right in...

I would love a system so people can't double book...but I doubt it can be done...