Why are you worried about your boat falling off the trailer? If you unhook the boat from the trailer before you are in the water, or you don't hook it up before you pull it out, you're going to end up regretting it in the long run no matter what kind of bunks you have. Your boat will take a dive at some point, as has been recently illustrated on this very forum.
I'm not. My bunk boards were shot and I like for my gear to be reliable. This is my first boat, and I know in 2015 there are many more options than just carpeted 2x4s. I just wanted to make sure I got the best solution for me.
I did use the liquid rollers though, and dang. They are slick. Yeah, you don't unhook until you're in the water, and you don't pull out without tightening down against the bow roller. After putting that Liquid Rollers on my new bunk boards with new carpet from Bass Pro I am convinced that it would be very easy to pull up and have the boat slide plumb off the trailer and leave it laying right in the middle of the boat ramp. It does make getting that boat all the way up to the bow roller stupid easy. I bumped it a bit harder than I planned this evening. I am going to have to get used to the new slick bunks.