Aliasing 80s -> oldschool.

Reason: Simple tag implication.
Also would suggest same for 60s and 70s.

Then you meant to title your post "Tag Implication" and not "Tag Alias".

Implicated the three.

Actually, according to the wiki's, oldschool was for pictures drawn in the style of 80's and earlier art, whereas 80's (and presumably the others) was defined as art actually drawn in the 80s. There was quite a bit of pollution in both tags, though.