Your data on lottery winning witholding may be out of date. Powerball and Mega Millions prize over $500 or $600, can’t recall exact amount, have both Fed, State, and sometimes local with holding on prize payouts. Fed is just under 40%. So I rather doubt PCH winners, being such juicy targets are exempt. Win a car, boat, whatever, you owe taxes and the gov gets theirs first. You may or may not recover portions of that depending on your tax situation.
Based on my experience of winning a 5 figure prize some 20 years ago. Don’t imagine the IRS has relaxed their talons on this matter.
Yes you may be right in that lotteries will withhold your tax liability for you and send it to the IRS on your behalf, like an employer for his employee. If you so choose to let them do so.
However, I maintain my central point which is no reputable lottery will contact you to demand you pay your tax liability first before they will give you your winnings. They will at most do what is above: give you your winnings at the same time they withhold a portion of it to pay the IRS (and/or state and or local taxes), again if you elect to do so at the time you win your prize.
In other words one will never be asked to pay something before receiving winnings. No reputable organization involved in games of chance will do that.