The policy at our building is that, if you don't feel comfortable, let the person follow you in, but let security know. We have the advantage that all entrance

The policy at our building is that, if you don't feel comfortable, let the person follow you in, but let security know. We have the advantage that all entrances end up going through a central area, and we have ample camera coverage, such that security can reliably find people who tailgated if they are informed. Tailgating is actually a very frequent and problematic occurrence for us, sometimes by people who will be aggressive, and this has seemed like the safest solution for us.