I just finished writing a small data update utility to copy a single row of data from a custom written application into a piece of packaged software. Usually when I do this I turn on Profiler, watch the packaged software insert a row and then copy what they did. This helps me find all the odd little status fields and related tables that aren't obvious from looking at the table. And yes, if the developer provided documentation it would help. They didn't.
This is a companion discussion topic for the original entry at http://billg.sqlteam.com/2007/08/24/viewing-database-updates-through-odbc-using-profiler/