lx3h, do u read Chinese? Some thoughts on your warning signs FYC:
Upper left: 我需要這充電位,卻用不上。如非充電,請勿佔用充電位!
Lower left: 這不只是泊車位,亦是充電位。如非充電,請勿佔用充電位!
Upper right: 請為他人設想。如非充電,請勿佔用充電位!
Lower right: 己所不欲,勿施於人。如非充電,請勿佔用充電位!
If you think 佔用 is not strong enough, you may use 霸佔 instead.