While college shopping? More than just college shopping -- forever after!
How about every vacation (was the kid ever actually in class?) and afterwards while she was in London. And what about the time that they sent AF1 back to CA to bring her books to Bermuda because she forgot them (this was during the Monica episode when Chels was required to attend her mother and father every minute in order to keep them from killing each other!)
What about traipsing her and her friends off to the Olympics in Sidney and hour tours of China, Africa, SE Asia, and the Middle East? All of them with several friends to keep her company.
They took 800 people to China and 800 people to Africa with them. Have you ever heard of diplomacy conducted with such a huge entourage? This reminds me of Cleopatra visiting Ceasar in Rome!
They could have Fed Ex'ed them. Chelsea was more likely hiding out from the utter humiliation of having a father like Bill Clinton. God help those two sociopaths if Chelsea writes her memoirs...