I've been thinking about this so that I can have my daughters stand to cast in my canoe. I can do it comfortably, but my daughters are wiggly and not terribly physically aware. A little extra precaution would make me more comfortable. Then again, a month ago my youngest daughter was dancing on the front deck of a sailboat while it was listing 20 degrees and going through chop. She'd make a decent pirate if she were allowed a dog instead of a parrot.
Cartop Kayak Carriers
URCHIN Portable Anchor