The law behind those checks is recent. Under the limousine safety package announced by the New York State Department of Transportation in 2020, stretch limousines converted from January 1, 2021 must carry a seat belt for every passenger, older vehicles had to be retrofitted by January 1, 2023, drivers of limousines carrying nine or more people need a passenger endorsed commercial license, and drivers of large for-hire vehicles are tested for drugs and alcohol before they are hired and at random afterwards. The state can impound a stretch limousine that fails inspection and keep it off the road until it passes.
You can check any operator yourself rather than taking a website's word for it, ours included. NYSDOT publishes inspection and safety performance data on Safe Limo NY, and carriers that operate across state lines have a public record on the federal SAFER company snapshot. Ask the company for the details you need to look it up. A company that hesitates has told you something.
The same rules decide where your group can drink. New York's Vehicle and Traffic Law section 1227 prohibits drinking and open containers in a vehicle on a public road, with one exemption: passengers in a vehicle designed to carry ten or more people that operates under a state or federal transportation certificate or permit. That is why adults can raise a glass on a properly licensed party bus, and why the same bottle in an SUV or a sedan is a traffic infraction for whoever is holding it.
NYSDOT also asks passengers to look at the vehicle itself before boarding: worn tires, lights or turn signals that do not work, an unusual engine or muffler noise, missing or damaged hardware such as door handles, and a damaged interior. A vehicle that arrives clean and free of visible defects is the minimum. If something looks wrong, NYSDOT takes reports on (518) 457-6512, and you are entitled to refuse to board.
None of that changes the drinking age. On any booking that includes passengers under 21, alcohol is not allowed on board, and that is agreed in writing before the night rather than argued about at the curb.