I did use big tie downs once, the day I picked my machine up. I felt so sick to my stomach all the way home that I went and bought chains and boomers the next day.
My biggest concern is fraying or tearing if they rub on a sharp metal edge. Axle straps are different as they are often reinforced with leather or something tougher. Great for bales or lumber, not so great for metal IMO.
You guys have all spent 20K, 30K or even 40K + on your machines, and they're obviously very important to you all (like me, otherwise I wouldn't see you names on here almost everyday!!!), so for God's sake, go out and spend $150 on four 8' chains, 4 boomers, and 8 quality hooks and sleep better at night!!!!
Like I said regarding pulling a 4x20 on a 7k trailer - even worse would be your machine ending up in the oncoming lane of traffic and you being 'that guy' that killed the family in the minivan.
That's my rant. Just something to think about.
-Jer.