I did...on my Eclipse Baltic cruise last summer...
I stopped packing my tux on longer cruises and when I go to Europe...because:
1) It saves room in my luggage...and with all of the weight and size requirements and extra baggage charges, it just does not pay. I even rented a tux for my 7 night Caribbean cruise this past January--because I could fit the rest of my clothes in a carry-on...American Airlines would have charged me $25 each way had I packed and checked a larger suitcase...and the cost of dry cleaning my tux and laundering two shirts where I live runs around $30-35...So, I figure I saved almost the entire cost of the tux rental!
2) When packed and then hauled around for a pre-cruise, the tux becomes wrinkled and messed-up...and it's just one more item (actually several with shoes, tie, cummerbund and acoutrements) to have to stuff back in the suitcase for the flight home...
Renting (or "hiring" as they say in the UK) a tux is easy...You give them your measurements (A local mens' shop will usually measure you for free as a courtesy)...and, when you get to the ship, the tux is usually waiting in your cabin closet...After the last formal day, they pick it up and take it away...
The entire cost (with shoes) comes to around $100...
Because I am an Elite Captain's Club member, I received, when I boarded, a coupon worth some percentage off of that--which I got them to apply retroactively...
I'll rent again on the Century in December and on the Eclipse again next July...