Civic Responsibility - 2018 version

We must be really civic minded here in Wisconsin.  We seem to have more elections than most places.  Today was a primary in advance of the upcoming mid terms.

So I voted.  I pretty much always do.  The drill is routine.  It's always the same place, a meeting room at the library.  Three of the four election judges are long time friends.  I sign my name.  I show my ID.  I vote. 

Then it is off to run errands.  At Target a talkative checkout clerk said he liked my sticker:

He said he thought that everybody should vote and started to tell me about his 18 year old sister who had difficulty voting despite having proper ID.  He did not get too far into the tale - I imagine it had something to do with current residency address - because he was after all ringing up my purchases.

Then he asked me for my ID.

I suppose I should have considered that he was kidding, although he seemed an earnest young sort who would have difficulty pulling off a subtle joke.  And it is also not wise to potentially annoy your customer base.

No, because I was buying a four pack of beer (Lazy Monk Citrus Heffeweisse!) he said that store policy required me to show ID.

So regarding the requirement to show identification I submit the question.  Was his sister, perhaps attending college or some such, more likely to be voting in the wrong district or am I perhaps more likely to be trying to purchase alcohol ahead of my 21st birthday?

I know, I know, he's just a guy doing his job.  But he is also a member of the young, upcoming generation who seems to find the concept of true irony incomprehensible.