They check by asking for valid photo ID.
Valet
The legal gambling age for Missouri casinos and slot machines is 21.
18 in some tribal casinos, 19 in other tribal casinos, and 21 in the non-tribal casinos.
The minimum gambling age is not uniform at all casinos; it is 21 at some casinos and 18 at others.
21
In the state of Michigan, you must be at least 21 years of age to gamble in the commercial casinos in Detroit. The casinos that are run by Native American tribes however, can set their own minimum age, but it can be no less than 18 years of age.
None. The legal gambling age for casinos in Indiana is 21.
The novelty of a new casino can draw away customers from the older casinos. The older casinos stand to lose the revenue generated by those players. It is usually just a matter of checking out the new place and most return to their favorite casino, when they don't it affects the casinos and their employees.
Bad ones
It depends on the casinos. Where the rules and regulations vary from place to place. In online casinos like billstop24 the age restriction is vary from 18-21. And also you will find the reviews of different online casinos in this website.
It's depend on casino (Barona Resort & Casino, Gold Country Casino & Hotel, Sycuan Casino etc.), there are casinos in California in which 18-year-olds can access some or all of the gambling areas, so you guys need to check ;)
You have to be 21. 18 in SA