That's a good point. In Double Shock, the maid had a lot of respect for her deceased employer and hated Columbo, but the opposite in Murder of a Rock Star. The same is true to a lesser degree in Forgotten Lady and Dagger of the Mind (although those were butlers rather than maids).

The maids that liked Columbo the most were always of one type of ethnicity -- the Polish maid in Sex and the Married Detective and the Hispanic maid in It's All in the Game (isn't that Rosario from Will & Grace?).