It's not uncommon for airline employees to have non-standard living arrangements, though seems more common to use apartments with 4+ people to a room with beds

It's not uncommon for airline employees to have non-standard living arrangements, though seems more common to use apartments with 4+ people to a room with beds filled based on first come, first serve; basically time-share like low cost version of AirBnb. Using trailers and employee parking lots sounds expensive for the employees and airlines too. Beyond that, guessing it's noisy and that theirs not much of use close to the parking lot.