Perhaps. But a wlan card taken from a discarded/stolen/recyled/used corporate machine, then transported half-around the globe and sold for cash, isn't necessarily easy to trace back to a perpetrator.

Often they can be wiped as well.

In some cases yes, but that requires additional expertise.

Not much. The OS has a utility to do it.

What? ifconfig or My Network Places in Windows. Adapter cards had to have their mac address programmed once; it can be done again. Its firmware.