Using an init.sqf to set civilians hostile to the player (in the tested case, independent setFriend[civilian, 0]; civilian setFriend[independent, 0];) causes the non-hosting players to sometimes be unable to enter some vehicles.
The behaviour is inconsistent, as in some tested missions both players were able to enter all vehicles consistently, while in others the bug was consistently present. {F20929}
Step 1: unpack the included .rar to MPMissions folder
Step 2: start a multiplayer server
Step 3: play the vehicletest-mission with a friend
Step 4: try to get in all of the vehicles
Step 5: observe as the hosting player is able to enter all vehicles, while the client is not
Step 5: play the vehicletestNOSIDE-mission
Step 6: try to get in all of the vehicles
Step 7: observe as both players are able to enter all vehicles
In one version we tried, both players were able to enter all vehicles even with civilians set to hostile, but I haven't been able to reproduce the same effect afterwards. I also deleted the mission, so I cannot provide a .sqf that works as intended.
Mass closing ancient tickets with no activity for > 12 months; assume fixed or too trivial.
If this issue is still relevant in current dev build, please re-post.