Loren Pechtel said:
Rather, we are saying that being in a bar implies she is of legal age.
Right, Tom is saying presence in a bar ==> legal age.
I am saying, even if we ignore the bar/restaurant point that many bars are technically restaurants, presence in a bar does not imply legal age. One reason is that people do not behave legally all the time. Underage drinking is common enough that everyone knows about it and so there is not an expectation that a 16 year old in a bar is 21. Moreover, people do not draw conclusions based on one factor, but rather look at the available things around and make an inference. So, some other factors contributing to inferences would be that she is not going to be fully grown, nor fully mature, especially hanging out with several girlfriends being drunk, only one of whom apparently has a car.
But there's more to this. We are talking about Louisiana which has a long history of a drinking culture, including underage drinking sometimes supported by adults. A long-time Louisiana resident in ~2005 would be aware of the Louisiana drinking culture and how minors are often supported in their drinking. This includes big legal debates, drinking culture, and crazy things people do at mardi gras.
That culture is best summed up by an anonymous bar owner comment, quoted in a
1996 New York Times article:
Uptown, a bartender in a hotel lounge said that all the talk of age limits is moot in the culture of Louisiana, where looking the other way is tradition. After the Supreme Court's decision came down, a young man came into his bar and asked if the drinking age was indeed 18. "Son," said the bartender, who asked not to be named, "if you can count to 18, I'll give you one drink."
Here is more:
Louisiana has a lawless mentality - a mindset that permeates every level of thinking. It's an attitude founded in the way we think about underage drinking. ... A 2006 survey by the National Household Survey on Drug Abuse found 29.97 percent of Louisiana residents age 12 to 20 reported alcohol use, the highest in the South.
...particularly relevant since we are discussing an event that occurred in 2006.
A 30 year old man in 2006 in Louisiana is going to be aware of all the underage drinking that occurs in Louisiana since he grew up there, likely participated in it, and will have been constantly reminded of underage drinking since between 1986 and up to that year there were many political campaigns about awareness, legal debates, tragic news stories.
It therefore makes no sense to take one factor in isolation, ignoring everything else contrary in the Universe, and claim it implies he thought she was definitely 18.