i think you make a mistake with the rule that IO can ask to see 20.000 in cash in order to let a visitor into the country. (to prove they can support themselves) It is not a "fee".
based on which ground this fee is supposed to be paid ? It is clearly written at the airport to not give any money to IO's. This story seems fishy to me.
That's what i said. This is not a law, and there will be no other consequence that a tiny risk of visa rejection. So this is not an offence, and not a crime. Thanks Mr obvious