If the EU wants to arrest someone they can submit an extradition request which the US will approve or deny after reviewing. The EU can also already arrest individuals whom are found to be criminals.
You are suggesting a totally new weapon for EU law enforcement which is to imprison individuals who are not found guilty of a crime because they work for a company that owes the EU money. That sounds a bit insane to me, I think if the EU wants to collect their fine they should find a more diplomatic approach that does not equate to a literal war crime [1]
The flaw in your line of thinking is that it is legal and very common place to arrest people who are suspected of committing a crime.
We're talking about people who have suspected of committing a crime in the EU. Should they step foot in the EU the EU is free to arrest suspects of a crime and they can get their day in court.
You are suggesting a totally new weapon for EU law enforcement which is to imprison individuals who are not found guilty of a crime because they work for a company that owes the EU money. That sounds a bit insane to me, I think if the EU wants to collect their fine they should find a more diplomatic approach that does not equate to a literal war crime [1]
[1] https://en.wikipedia.org/wiki/Hostage