Re:RF Monitor Mode (Score 1)

And you can't "detect" a hunk of metal out there picking up on them. Almost all new cards are capable of being put into RF monitor mode and sniffing raw 802.11b frames without transmitting anything.

While I agree with your main point, just a point of fact. "You", the average tech might not be able to detect a card silently sniffing. But "They" certainly can.

An RF receiver is certainly not undetectable the way a RX only wire sniffer on a analog tap is. When an antenna receives a radio wave it retransmits some of it, and also transmits noise from the circuitry. This was used in WWII to find spy radio receivers, and is also the principal behind tv detector vans in countries that enforce tv licenses.

While a wireless card would be harder to detect given the other noise in that band, they'd be easy to find for any technical security team doing a bug-sweep and appropriately equipped. Any government agency doing those sorts of technical security checks shouldn't find wireless snoops hard to find. It may even be a useful way for them to spot local amateur penetration attempts.