Final answer:
The best thing to do if you are unable to prevent a drinker from driving is to call a taxi for them. Offering to drive them home yourself is also an option, but not always feasible or safe.
Step-by-step explanation:
If you are unable to prevent a drinker from driving, the best thing to do is call a taxi for the drinker. This will ensure that the drinker has a safe and alternative mode of transportation to get home without driving while under the influence. Offering to drive the drinker home yourself is also an option but may not always be feasible or safe, especially if you have been drinking as well. Confiscating the drinker's car keys can also be effective in preventing them from driving, but it may lead to confrontations and is not always a practical solution. Letting the drinker drive and hoping for the best is not recommended as it puts the drinker and others at risk of accidents and harm.