I don't think thats true, the area the Royal Caribbean cruisers go to on Labadee is private and there are no other private tour companies that operate there. We did the waverunner tour and it was great fun, but if you want to do it, pre-book it, fills up quickly. BTW, its $99. per person and 2 people go on one, but its a guided tour and very interesting. If you want to go faster, let them know and they'll put you in front, although from time to time you'll have to stop and wait for the rest of the group to catch up.
We did this excursion last jan. No one other than RC to rent from on Labadee. For DH and me, the $99 included both of us. The $99 is per waverunner and you are allowed 2 people on one...unless they've changed the rules cuz that is all we paid.
Carnival Festivale 8/95
RC's Navigator of the Seas 1/24/04
RC's Brilliance of the Seas 1/14/05
Disney's Wonder 9/18/05