The only way you (American citizen) can cash a ticket in the sports book that will trigger IRS tax withholdings (a W2-G) is if you cash a winning ticket that
1 - hit odds of 300-1 or more, and
2 - had a payout of $600 or more.
Very rare in the sports side hitting parlay or future bet that pays like this, more common in the race book side with their superfectas and such.
the $10,000 cash reporting deal (sportsbook does the paperwork, you provide the ID and SS#) is also an IRS requirement - but it has no tax implications. It is for tracking large cash transactions for purposes of monitoring possible money laundering.
different parts of casino can have way different rules in tax withholding. For slot machines, etc, it's $1,200 limit that will trigger taxes. The racebook has a few more I can't recall. Ya got that $5K thing in poker rooms, etc...
But in sportsbook you can hit a 5-way parlay that you put $5K on and payed out $100K and you will suffer no tax withholding on this because it was 20-1, not 300-1 or greater. You can hit a straight bet and win $100K, cash that, and similarity -- no taxes would be deducted from your payout.
but taking all those winning in cash would trigger a CTR (Currency/Cash Transaction Report) to be filed on you. For this you must show your ID and give your tax ID (Social Security) number because cash of $10,000.01 or greater was passed across that payout window.
The $10K deal is any cash transaction. So if you put $10.5K bet on the Steelers, the book will generate at CTR right then, when you placing the bet. Easy for them to do the CTR if you give 'em players card - with that card they can get all the info on computer instantly for the IRS form.
The CTR is not filed for any tax purposes, the IRS does this to track large cash transactions in their fight against money laundering.
If you cashed the big win at casino cage and asked for $10K cash, and the rest in chips (i.e, not cash or currency), the casino would not have to file a CTR on your lucky ass. But that's pretty damn suspicious you are committing a crime called structuring (deliberately structure payouts in manner to avoid CTR), so they'd most certainly do, as required by law, file a SAR (Suspicious Activity Report) on you. SAR is triggered at a $5K threshold.
But most cages are pretty suspicious and a picky lot too, so they'd most certainly ask for ID in this instance, as they assuming you'd cash in the chips soon - the $10K CRT reporting threshold is an aggregate amount over a single 24 hour period.
They would also check your MTLs, even for $5.5K payouts. The MTL is a "Multiple Transaction Log" that records $5,000 or greater transactions. Every gaming pit records these, or employees involved in chip redemption, chip purchase, markers payed in cash, safekeeping deposit, payoff in cash, etc. MTLs aren't for the IRS. MTLs are an in-house deal casinos do to track transaction activities that may trigger CTRs and SARs.
For example, the casino, with these MTLs, finds you moved cash of $10,000.01 or more across that casino cage (or sports book window) in separate transactions in a 24 hr period, each below $10K, but totaling in aggregate at least $10,000.01 - then they will file a CTR on you. And maybe a SAR too, if it looks suspicious (you do it often, look like drug dealer, counterfeiter, etc.) SARs aren't filed much, but you get enough of them and the IRS or Secret Service will want to meet and greet you. This is not a recommended social activity.
CTRs are filed all the frikkin' time and hardly anyone ever pays much attention to them.
If you refuse to show players card, or ID and SS# when they ask - then they will note that in a file, write up a description of you, probably 86 you from the property, won't cash your ticket, flag it so no one else can cash it until proper info given (and ask if you a runner for someone else too).
And, yes, if you Canadian, Mexican or from them other furrin nations who have no gaming treaty with U.S. (there's a lot of 'em), you will be subject to an automatic 30% in taxes withheld. Countries that do have the treaty (Czech Republic, Denmark, Finland, France, Germany, Hungary, Ireland, dozen more) you just give them yer I.T.I.N number and you get no tax taken out.
Tho Canadians [under Treaty Article XXII (Protocol 3)] you can offset your gambling winnings with gambling losses by filling out the Form 1040NR return, and get some refund.
IRS W2-G CTR SAR MTL I.T.I.N Treaty Article XXII 1040NR
(casinos love the Federal Government as much as ex Las Vegas Mayor Oscar Goodman does)