They often go around and put locks on spaces that were left unlocked. You could get trapped in there.
The smallest units were not any doors like a garage they were 8x10’ with steel doors and deadbolt which by law had to have keyless knobs on the inside to keep people from being locked in. It helped that my friends family owned the property and looked the other way they knew I was in the delayed enlistment program and had nowhere else to go until my slot came up.