The rule of ROPS use is: Always use seatbelt if it's up, NEVER use seatbelt if it's missing.
BTW, old tractors can be retrofitted to make them safer. Too many farmers have been injured or killed by old tractors without ROPS/seatbelts, unfortunately.
As an adult you're free to choose to do what you want, and pay the consequences of your mistakes/errors.
Not a slam, just reality.
My rental prop next door has a very steep bank leading to the pond. Last summer I was mowing with my Wildcat, ROPS up, belt on. I was doing the same track I do every time I cut and next thing i know the Scag takes a sharp right turn down the bank. I'm half way down the hill when i am able to get control of the machine and trying to figure out what to do next. Backing up the hill will only render ripped out grass and bare spots - so I decided to go forward until I can rest the weight bar against a tree. I left the keys and walked away. Came back with the Kioti and after releasing the hydrostat motors dragged the Scag back to level ground.
First time I went over a smaller hill I pushed the handles forward like I was stepping on a brake pedal- hit a sapling hard. By the time the above hill happened I was'trained' to pull back to slow forward momentum.

:confused2: