There are walls and other things in the ghost hotel on altis that are only there visually and physically for the player. The are completely permeable to bullets, light and AI targeting.

• The AI can see through them.
• Bullets fly through them without actually hitting anything
• Lasers and lights extend through to the other side

I tested as many walls and objects as I could that have this problem and I came up with the following list:

1
Object: Wall
Location: Between main lobby (on the 'middle' floor) and the first hotel room. This also counts for the same room in the other wing.
Problem: Anybody can shoot or shine a laser through the wall, both from the inside out and the outside in (both in the actual room and the bathroom). AI do this, even though they shouldn't be able to see through that wall.
See: Picture 1

2
Object: Building Pillar
Location: this pillar is closest to the elevator shaft in the main lobby. This counts for the 'middle' and the top floor of the lobby. The others pillars do not have this problem.
Problem: It seems that bullets and light will fly through the half of the pillar (the half furthest away from the elevator shaft) without any problem, making it useless as cover
See: Picture 2

3
Object: left counter
Location: This counter is on the left when you enter through the main doors.
Problem: I am able to shoot through the counter and hit the floor without ever actually hitting anything in between. Again, the AI can see through and will shoot, making it useless as cover or as a hiding spot.
See: Picture 3

4
Object: Doorway.
Location: On both stairways furthest from the lobby, the doorway on the 'Middle' floor.
Problem: The walls next to the door are completely permeable as described above, making them useless etc.
See: Picture 4