The elite have already been forbidden from entering or doing business with the EU since November.
What, specifically, does this mean? The EU sanctions, idk, the Bahamas? Who? And how?
To literally "seize" the money stored in an offshore bank account is difficult unless the EU is also willing to march an army into those countries.
Nobody ever touches offshore havens since rich people from everywhere have money there.
It took 9/11 for Switzerland to not laugh at law enforcement request from other countries. (Probably still laughs to anyone thats not US and maybe EU)