This is a reminder to not allow unauthorized people into the building.
If you do not know them do not let them in (unless you have been authorized to let them in by the resident).
Guests should be directed to the front lobby intercom.
Some residents have commented that unexpected guests have been knocking at their unit doors and said someone let them in the building.
Also, do not keep doors propped open unattended.
Thank you for your attention to this matter.