Over the course of several trips we've only had one reservation screw-up and when the hostess said there was no reservation under that name I pulled out my number. Finally after several minutes she found it, booked under my husband's first name as his last name and some completely different last name. Luckily the number saved us.
A bit OT - We've had far, far worse experiences with the whole reservation thing when OTHER people run up and claim OUR reservation when the name is called at the restaurant. We love how the Cali Grill uses beepers and the LTT uses the name and state. And our last name is totally unique and couldn't be easily claimed by others yet it was several times!
And several times we have waited patiently with our ADR while walk-in parties of the same size were seated before us. This has really soured DH at several restaurants in MGM. One time, it riled me so much that meek ole me, actually walked up to the hostess, armed with the facts and told her how many parties of 3 had walked in and asked about seating and been shown to a table while we had been sitting there! We were quickly shown to a table and even offered a quick apology.