[HAL9000]

Atheros - Open Source Linux Driver Now Available for Atheros 802.11b/g and 802.11a/b/g Chipsets

I'll speculate that a common code base exists for the Windows, Linux and Mac drivers for the Atheros chipset, which allows the exploit to access all of those systems.

[HAL9000]

If I was a Black Hat, I'd be looking at this file -

http://madwifi.org/browser/trunk/net80211/ieee80211_scan_sta.c

I don't know if this would help prevent the problem, but as a countermeasure on a Mac with Airport, I'd suggest setting the "Join Preferred Networks" and "Ask Before Joining Open Networks" options.