sorry, gonna have to disagree with you here. you ever do any construction? to make floors more rigid/prevent deflection, you can add a 2nd sheet of plywood to the top of the first and simply screw or even nail it in place. this is similar to the rosette welding process as the 2 sheets do not have to be "glued" together to still provide the desired results. IF the tolerances of the sleeve were so tight that a press was required to install them (much like axle tubes are pressed into a differential housing and i should add, STILL get welded in place), you might have an argument BUT, if you can actually just hammer them in, i have a hard time believing there would be enough friction to do much of anything. even if the sleeves have teeth, there aren't any on the inside of the axle tube for them to grab onto or, not that i know of anyway so not only are they irrelevant, they would in fact REDUCE the amount of surface area that would otherwise provide friction.
what it all boils down to is that this company realized that there are a lot of scared people who feel the need to beef up their axle and don't like the idea of drilling holes and welding things. needless to say, they came out with this do it yourself solution and really, it's a great marketing scheme and one that might even provide a tiny bit of extra strength. but, unless someone can prove otherwise, that's about all it is. of course, that's just me.
great episode but, i hardly think that teeth on a tube would give you the same frictional bond as a thousand sheets of paper essentially laminated together.
