Could you get customers to buy even more?

I'm heading to Chicago today to attend Andy Sernovitz's day long World of Mouth Crash Course on Wednesday.  (I'll tell you all about it when I get back.)  The event begins with a dinner tonight and then 10 packed hours of no doubt some serious learning and some serious fun.

So…I get to stay overnight in Chicago, one of my favorite cities.  And it also boasts one of my favorite hotels — Hotel Burnham.  I made my reservations online and within an hour or two of receiving my confirmation e-mail, I also received what I am calling the upgrade e-mail.

The strategy is simple.  I have already made a purchase (or in this case, a reservation) and now they're going to invite me to upgrade my purchase for a small additional fee.

The airlines have been doing this for awhile, selling more legroom, exit row seats, etc.  But I am seeing more and more businesses of all varieties using the same technique.  It's much easier to get someone to spend a few more dollars as a perk, than it is to get them to choose the deluxe option from the get go.  Or in most cases, they probably didn't even consider the deluxe option or know it existed.

So here's the interesting question.  How could you use this sales technique with your customers?  Do you think this only applies when you have a product to sell or could service industries use it too?