I'm also having a hard time with this...
I seriously don't want to sound condescending, but it's not hard to strap a wheeler down inside the bed, utilitrack or not.
And, I also have a hard time believing that a 600# (if that) wheeler can actually cause a truck to flip over because it's strapped down - I would, however, believe that a 600# wheeler *could* cause a turnover if *not* strapped down, and I also believe that a 600# wheeler *could* cause a death (your own, your passengers, or some '***hole' that may cut you off) if it broke loose and jumped the bed...right into your cab or the '***holes' windshield.
I apologize...I guess that I don't understand. Could be that white_titan05 is upset that he's got a bed-extender thats not working the way it should? After all, straps are cheap, reliable (if you get some decent ones) and pretty much required if you're hauling a heavy load.
Myself, I have 6 pairs of heavy-duty ratchet style straps in my bed tool box.
This is one of those cliches that won't go away: Better safe than sorry!
Again, White_Titan05...I'm sorry that I don't fully understand the problem you're having, but I do have to say that an unrestrained 600# in the bed of a truck is *far* more dangerous than a restrained 600#.
Psychlone