Many hotels don't have rooms with '13' on the doors.
I ended up with a frustrating networking problem when helping install an IPTV system in a Spanish hotel a few years ago. The contractors had wired an IDF on each of several floors in the hotel. The job looked neat enough but we were seeing some unexpected behaviour, so we started tracing the cables..
- port 1 was connected to room 101 (201, 301, 401...)
- port 2 to room 102, 202, 302 ...
and so on, as expected, until ...
- port 13 was connected to room 114 (214, 314, 414, ...)
and so on for all the remaining rooms and floors (fewer than 13 thankfully).