I don’t think it’s just you, but I’d never heard someone refer to the registration decal as a tag before you.

I asked ChatGPT in the most neutral way I could think what “tag” meant in relation to motor vehicles just to get an aggregate perspective on what the internet at large says and it turns out both are definitely common:

I wonder if it’s geographic or what. Its odd to me that we both had only encountered one usage and it was the opposite

I was pretty certain Florida did. At least when I lived there decades ago…

It sounds like maybe you’re talking about the registration decal when you say “tag”.

Virginia requires them on both front and rear plates.

most of the East coast

North Carolina also does not do front plates

Yes…

…except you clearly forgot about Rogue One.

Mine is they shouldn’t have made the sequel series without George as a consultant a plan

I dunno - I’m pretty sure I’d choose the modern MacBook Pro’s ports over any of these other options.