802.11: To 'B' Or Not To 'B', That Is The Question

I seem to do some of my best thinking when I’m exercising, and when I’m drifting off to sleep at night. As I mentioned yesterday, last weekend I switched my 802.11b-inclusive laptop’s LAN connection from CAT5 to Wi-Fi. However, I remembered last night, mid-last week I’d reconfigured my Linksys WRT54GC router’s wireless subsystem from ‘mixed’ mode to ‘G-Only’ (since, at the time, I wasn’t using any 802.11b-inclusive gear). So the laptop shouldn’t have been successful in connecting to the router…but it did, and in fact the connection’s been stable and solid for the last three days.

Ideas why, folks? And should I switch the router back to ‘mixed’ mode, or leave well enough alone?