No no no you guys are ALL wrong. He is not doing anything wrong. He is trying to do the right thing. He's using the plywood to keep the walker from sliding off the back! If only he had a ratchet strap to hold that board on there then everything would be kosher!
You know, funny story though. One time I told my self that I was going to teach myself how to arc weld. Well I decided to teach myself by building gates on a huge 22ft long equipment trailer with those type of ramps. I just added on standard expanded metal gate portions to the insides and took off down the road...well... i must of used the wrong type of rod or something cut about a week later i lost one half of my ramp in the middle of the busiest intersection in the city and didn't notice until I was at the next house 15 minutes away. that was embarassing to pick up....