(Apparently this makes sense because if gambling wins were to be taxed then gambling losses should also be deductible, and since gambling is inherently a losing proposition, the tax authorities would lose more than they gained. I don't really buy this argument since they could just tax winnings and offer no deductions, but hey ho.)
Welcome to the modern Western society, in which employees have been reduced to litigation-avoidance automatons. No wonder so many people hate their jobs, stripped of any power to help or even just follow common sense.
I know in some lotteries and sweepstakes they tax the pool, and so the winnings are tax free to the winner and the taxman invisibly still gets his cut.
I don't think this would make sense. If I walk into a casino with $200 and then proceed to lose $100 and win it back 10 times, then I lose it all and walk out, that tax law would say I had "won" and had to pay taxes on $1,000 even though any reasonable person would say I had actually lost $200.
In practical terms, I think it would absolutely ruin gambling addicts. This makes it effectively impossible to actually net profit, and I'm doubtful they'll stop.
I googled because I was curious and found an article about it [1]. It's similar to PayPal/Venmo/etc. Once your winnings meet certain criteria, the casino has to give you an IRS form (W-2G) and they presumably send another copy to the IRS.
The withholding part isn't super clear, but I guess under some circumstances they also withhold 24% of those winnings to pay federal taxes.
1: https://www.hrblock.com/tax-center/income/other-income/gambl...