Greetings! I currently use the pictured lap tray with my Permobil chair. When being evaluated for a new van, the evaluator advised against having the tray on while being transported in case of airbag deployment in an accident (I sit in the front passenger area). While I could have the tray removed and replaced while being transported, it's a bit of a hassle (admittedly nothing major!), but I was curious what others use. I often place files on it for work when meeting with clients. I've seen ones that rest on the legs, my only concern is if the tray or papers would start to slide on my legs, I'd have difficulty keeping them from falling (especially when I tilt). Just thought I'd see what others use!