Moved hundreds and hundreds of games, never lost a one, and I've had my oh crap moments... Some people say I overstrap and am too worried, I call it insurance and a 100% chance that the cabs don't go flying when I have to do that emergency maneuver because of some other a-hole or animal on the road.
I've never once seen anyone pickup a game from me who went nutso on straps like I do and I've seen and heard horror stories. I'm an advocate for putting 3-5 straps per cabinet depending on shape, size, and if they're standing up or laying down. I run them from each and every direction, angle and location on the cabinet. I also carry around a few 2x6 boards to set machines on so they're not directly on the bed soaking up water if it were to rain.
I was going 75mph at 3am on my way home from a LONG road trip with 3 or 4 machines standing upright in the back. Come around a corner in the highway and there's a huge elk right in front of my truck! I am alarmed awake and slam full force on the brakes! The elk is scared shitless and can't decide which direction to run. At the last second I decide steer for the ass and literally powerslide right by the massive elk inches from totaling my truck and possible life threatening wreck. The STANDING upright cabinets held just great, didn't budge! I've towed trailers with 12-14 games and had to make an emergency maneuver, nothing cut loose or was damaged. I had a ratchet strap snap on me and tore a 1" gash in the bed rail hole of my truck (metal fatigue from so many arcade haul strap downs). The two cabinets I had upright when that baby cut loose stayed perfectly snug because I had extra insurance straps covering the rest of the load evenly and from different directions. I had a guy who bought a game from me only use one strap on an Asteroids machine. I offered him a ratchet strap or two if he wanted to actually secure the machine instead of half ass it. He said no and went on his merry way. When he got to the stop sign at the end of my street I hear this SMASH! and his rear window of his truck blows out! He had that crappy hard plastic bed liner that everything slides like crazy on and thought one strap was adequate...
Why not spend an extra 3 minutes overly strapping the load more than what you think you'll need, and having a near zero probability of problems down the road?