I would also discourage operating the 3-point, FEL, or any other attachment when not at the operator's station because:
1. Being in the seat keeps you in a known safe location - the attachments are designed to not intrude or injure somebody sitting in the seat. If the machine rolls over, the seatbelt/ROPs will prevent being crushed. Its the safest place to be.
2. You are in control of the other aspects of the machine. The brakes, steering, etc. You are not going to have a run-away or roll-away machine. An operator in the seat will be able to deal with the situation a lot better.
3. Good habits like checking the state of all the control before starting the machine become routine every time you get on. If your standard routine involves checking the clutch and brake before starting, you are not going to have unexpected movement. Doing stuff from the ground takes the operator into unfamilar operations - they may not go through the quick safety routine normally used when starting the machine.
My own bad habit in regards to this is simply starting the tractor while standing beside it. If it was in gear and the safety interlock failed, it could easily run me over. Also, because of position control on the 3-point, the 3-point could lift unexpectedly on startup leading to the situation described.
- Rick
P.S. On checking the state of the controls. Now that I have a young child who likes to occasionally climb on the tractor when it is parked, there are a lot of extra precautions I need to take. A: When starting, any control can be in a random position - I can't assume its how I left it when I parked. B: I need to make sure that all the lift mechanisms are lowered so that random play on the supposedly inert machine doesn't lower something heavy, and also that even if the brake is released, the machine is not going to roll.
I know that keeping children off the equipment, even when parked is best, but its not always possible to 100% enforce, so additional precautions are prudent.