I have an iPad which was in use and showing connected to my wireless network however the last logged association to a WAP was two days previous. I get that if it remained on and connected to that particular WAP there shouldn't be another event but given that it was two full days (let's even call it a day and a half) and there is no way the device was on for the entire period (the location would have shut down for the night twice) it seems odd to me that I don't see a fresh association message being logged.
It's possible but not probable. The device is used as a mobile PoS terminal and is carried around the location. We've only got two waps so it's possible that it stays associated to just the one but as I look through log entries I see historically it and other devices moving between the two or re-associating after having been turned off or going to sleep.