Sounds like someone could turn this into a business venture.
Tray truck parked at a busy beach in summer.
Two rows of cube lockers stacked 5 high x 10, installed back to back = 100 lockers rented out at $5 per day.... Portable steps from the ground to tray.
On the front of the tray, two mounted portable changing rooms.
$5 fee includes locker key and free use of changing rooms.
Back of tray has storage for rental of beach umbrellas, small beach shades, surfboards. (Security deposit is taken in case of non-return).
Also sell suntan lotion, insect repellant, and other personal items.
Cool way for someone to make $500 to $1000 per day.
Hmm... The franchise opportunities.