Do you know what the penalty entailed?
If you are found working or staying in Poland without permission, you will be deported back to your home country at your expense, and will be forbidden from entering any country in the Schengen zone for one year. You may lose your visa-waiver status, and will have to apply for a visa to enter the Schengen zone after your year is up. However, since you are in the database as already having been deported, it is unlikely that a visa will ever be granted, so it works out to a long-term, if not lifetime ban from the EU, as well as from any other country that uses the database.
If the US embassy pays for your return, they will confiscate your passport and not reissue another one until you have paid them back in full the cost of returning you to the US.
If Poland decides that you owe them taxes, they have the right to detain, convict and even imprison you for tax evasion, or to detain you until you pay off your tax bill and fines. They can even confiscate all your belongings and whatever you have in your pockets or bank account. That will earn you a criminal record and a place on the dreaded Interpol database, which means that you will probably never be allowed to travel outside of your home country ever again.