I had the entertainment rate last year in March and they never asked to see my card. I have never heard anyone say that they were asked to present the card, but I would feel too guilty if I got the rate without actually having bought the book. You can buy the books on-line. Last year I paid $20 and this year I got a renewal for $15.
As for the distance of Sea WOrld to HIFS...I don't remember exactly, but I would say it was about 20 minuts or so. The HIFS website says it's 4 miles to Sea World. I do remember that it was a really easy trip!