yep this can be true.
at mambo in 5-6 ft swell (8ft+ sets at times) i was kiting and there was only about 8-10 knots wind and i was on a surf board, i went for a down loop carve on the top of a wave, and it was all going well untill i went towards the kite too much and the kite backstalled (probably not smart goin out in 8 knots in big surf) into the water and then the wave pushed me towards the kite and i went over my lines and got them wrapped around my leg. then the wave reached the kite and pulled the lines tight around my leg while the kite got dragged under water pulling me leg first down under the water. i was completely freakin out as that wave was the first of a big set and i couldnt release my kite as i didnt have a knife in my harness to cut the lines. every time i got above the water to breath another big wave would come and i swallowed water (and alot of it) by the time i got back to shore (5-10 mins later) i threw up and was feeling pretty s**t.

well u asked to share a story but the main thing is if u drop ur kite in the surf dont do what i did and try to rellaunch it if a big wave is comin just release it and the worst that can happen is someone will see ur kite and they will grab it off the beach if it is flying away and you will get out unharmed.
ewan