They may have brought their own.. or...
True story: I used to help folks at the family center connect.. You see the park had purchased a Linksys Home/Small office router (WRT-54G) and plugged it in, they did not even change the SSID.
Well, turns out that router will only assign 50 IP addresses, that's all, once it hits 50 you can not get an IP address so you will be "Limited".
I changed it to 100
Next day I'm helping some young lady connect,, I explained, and then logged in and downloaded the client list (Technically I'm hacking but I am careful to do no harm). (I also reported all this to the park manager so let's put it to rest before it's an issue).
I explained that when they first plugged it in about all that connected was laptops but now we have PDAs Game machines and oh, here's one "Suzie's I Phone"
Yup, she was Suzie.