Oh, Robin that sucks, at least you found it.
Luckily in 14 trips, we have never had that happen, but I always go prepared. This time, we have alot of reservations, so I have an app on my EVO and my Ipod and I will also have them written down somewhere.
In the past, I like to pay my tip in cash, so I make up envelopes for each restaurant and write the restaurant name and the confirmation # on the front, then put my tip money in there, each day, I pull the envelopes for that day out of the safe and stick them in my purse/backpack and have it ready just in case. Doing that eliminates alot of problems.