Well, color me wrong, perhaps. Unlike many here, I have no problem with lap children as mine, even the day before her second birthday, was just fine in a lap. However, I would definitely get this in writing on airline letterhead with a real signature, preferably in triplicate, before embarking on such a trip. The consequences of getting wrong information from a TA would be large, particularly if the flight is full.
I'd be interested in the experience of anyone who trys this.
Michael