All of my experiences flying with boats have been good, though it certainly involves the long-distance-runaround.
The idea that the price was set with the larger, older, more fragile boats makes sense, but when I flew with United in 2000, the price was $60 each way, but in 2005 they said it was $150 each way. This makes me think it might be due something else (9/11 possibly?).
I don't like to lie, especially because of the potential consequences of getting caught (not exactly sure what they'd do, airline fraud? Extra fees and fines? Confiscate your boat? Never heard any stories, so I don't know what happens to those who get caught). And about half of the times when I've flown with my kayak, upon picking it up, it has been obvious that it has opened and inspected. So it is certainly possible to get caught if you lie.
Some airlines claim to not let you fly with kayaks, so definately check up before you go to the airport and get the name of the person who told you it was okay (e-mail's great proof, too).
Show up early. Not only does it take longer to get things done in the oversized-baggage area, but I've shown up at like six in the morning and because there wasn't a superviser present yet, the attendant had to do what she thought was best (usually better than what the rules actually say).
What's worked best for me is hopping out of the car at the drop off with all my gear and handing a twenty or two to the nearest attendant. They'll take care of you. I even had one guy check our luggage for us.
If they offer, DO NOT PAY THE AIRLINE FOR YOUR BOAT TO BE SENT BOTH WAYS. I have never met anyone that this has worked for; you just get screwed (even with proof). Varying policies with different airlines, airports, and individual people's whims make it unrealistic to think your purchase will be honored upon your return. Typically you get a better deal if you don't, too.
"The world would be a better place if everyone kayaked."-Brad Ludden (Valhalla)
"You only get one chance to run a drop blind."-DD