This is a slightly different situation, but a few years ago I was behind a honeymooning couple at Frankfurt who had a ticketing problem because her ticket had been booked in her new married name - but her passport hadn't been changed yet. Even though she had her marriage certificate explaining the different name, she was denied boarding.

Frankly, I wouldn't take the risk of traveling with the wrong name on my ticket. You never know when someone is going to be picky. It could be even worse than having it happen on the way out - it could be on the way home. I would insist on the travel agent changing it.