Are you an expert of mac-address? Let me put it in the ways I talked in another meta question about creating some tag:
Do others think we need this tag?
For that questions I normally ask myself "Myself, what is mac-address?" and myself answers with a wikipedia dump:
A media access control address (MAC address) is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used as a network address for most IEEE 802 network technologies, including Ethernet. Logically, MAC addresses are used in the media access control protocol sublayer of the OSI reference model.
Then, I look another posts/tags that already has what mac-address means: "ethernet", "wireless", "network interfaces", "networking" other related terms/tags. Now, is the proportion of related terms big enough that it will make it difficult for answerers find the questions they want to answer? No? Then we do not need a tag.
Remember that tags aren't there for the users asking questions but for the users to find questions they want/could answer ;). I do not think we have an important proportion of users that would like to answer those kinds of questions, so NO, we do not need that tag.
So, the tag wiki needs to be modified (again) and tell us about networking which already cover any aspect of the mac-address tag. Silly tags, are unuseful tags. I'm not against the tag creation, I'm against the creation of a tag just because.