Yes, these small bases and space outposts have really limited number of landing pads, so it can happen even with just NPCs.
The landing pads were clear - however - as I said I was less than 5 km from station, but I logged out and back in to find myself 10 km from station! Approached, requested docking - OK - BUT!!
When about 1 metre above the pad the game "froze" I was going to log out and back in again,but went to the loo first - when I came back - "Ship destroyed by Federal Agents" damn this game!
Ticket raised - but how to estimate exploration data lost? If indeed Frontier will try to compensate for that - maybe just tough luck?
That's something else I think is hurting this CG besides having the beta ongoing, setting it at an outpost. For one thing, it automatically excludes anyone with a large ship, and then you have to take into account the limited number of landing pads.
I haven't yet been denied access because the place is full, but I can easily see it happening.
If you are within ship scanner range of the hangar then you can cycle through your targets to see if the hangar is occupied.
I remember during one of my first CGs that involved picking up some rares at an outpost receiving a polite message from another CMDR for me to hurry up, as I was in the hangar looking through Starport Services.