Can a MAC address be spoofed?
yes.
Can mac addresses be spoofed?
In normal network cards, yes.
But its really hard to do so with a wireless card because
access to this level of control is protected by federal regulation. (They can't let you tinker with the radio or all hell would break loose).
But even if hackers could change it, they would have no way of knowing which mac addresses are in your Mac Address list.
(Mac addresses are fuzzy addresses like 00-D0-B7-1D-F2-EB hard wired into the network card, and globally unique.)
yes.
"Can a MAC address be spoofed?"
Yes. Most Wireless Routers do this. The cable or dsl company only wants one computer per link. The router spoofs the MAC address of your compute so that all packets look like they come from one MAC address.
You have to know the MAC address to begin with to spoof it.
cloned.