Legally, while you may not like the social behavior, is should not be punished as a crime.

Socially, and for their economic future, this type of dress and behavior is easily rejected.

As I once told my neighbor's son, who was a junior in college; that lizard tattoo on your neck is a real attention-getter in college, but serves very little purpose on your first job interview.

Oh yeah, probably not safe for work.

Is this emanating from a penumbra somewhere or what?

The right to wear what one chooses is squarely within the freedom of expression guaranteed by the First Amendment to the U.S. constitution and Section 4 of the Florida constitution. No penumbras or emanations needed.

Idle (Judge): What is the charge?

Cleese (QC): M'lud, the defendant was showing his knickers in public.

Idle: How say the defense?

Palin (the other one) of the Bailey: M'lud, my client's knickers are none of the city's business.

Idle: What does the defendant have to say for himself?

Gilliam (defendant, affecting an English accent): I paid 10 quid for me knickers.

Cleese: Objection. The price of defendant's knickers is not at issue.

Idle (ignores Cleese): 10 quid? (stands up, drops trow) I paid 30 for these.

Palin: Crikey! You were taken M'lud. (stands up, drops trow, has same knickers as the judge.) I only paid 20.

Cleese: God's truth! (drops trow, has same knickers) I paid 25 for these.

[All three look pointedly at Gilliam. He slowly rises and drops trow, has same knickers as the others.]

Idle: Counsel and QC will approach the bar. [Palin and Cleese shuffle up to the judge, pants around their ankles. Murmured conversation. They shuffle back to their places.]

Idle: Defendant is fined 45 pounds payable in cash to the court (Cleese and Palin nod in agreement) and is remanded to custody pending shopping trip to wherever he got his knickers for 10 pounds. Next case.

What if, for example, instead of wearing boxers I wear colored track shorts with my baggy jeans, is that a violation?

It gets even more complicated than that. The new trend seems to be to wear a "private" undergarment under your "public" undergarment. Indeed, it seems an entire industry is cropping up to supply undergarments as fashion accessories and not as undergarments. So, legally, what is the difference between shorts and underpants, if both are being worn the same way?

Historically, though, states and municipalities have the presumptive power to regulate pretty much anything except where the U.S. or state constitution specifically denies them that power.

States, yes. I disagree on municipalities. Historically most municipalities are subject to Dillon's rule -- they have no inherent powers, but only the authority given them by the State. According to the following link though, it is not clear whether Florida follows Dillon's rule.

Dillon's Rule

Having no idea on what grounds the judge ruled, here, on these kinds of laws are probably facially unconstitutional for vagueness

That was my thinking as well. The first clue is that the law arose from a voter-initiative referendum. These are notoriously written poorly.

Historically, though, states and municipalities have the presumptive power to regulate pretty much anything except where the U.S. or state constitution specifically denies them that power.

James, you seem to be looking at this issue as if you were a federal judge. A Florida judge can do whatever the people of Florida have vested in the Florida courts to do.

The federal government is indeed supposed to look at states they way you describe, because the federal government was created later, by the states. But states and localities aren't born with power, the view I prefer to take is that they have only the powers that have been given to them by the people.

I shouldn't go any further since I don't know the applicable law, but just for fun . . . I wonder if it would have violated the law at issue to walk around only in your underwear? How does one legally distinguish boxers from shorts? Or could you violate it only by putting the pants on, but not high enough? And what happens if localities start adopting all sorts of unique laws re appropriate dress, how is a traveler to keep up with them?

What if, for example, instead of wearing boxers I wear colored track shorts with my baggy jeans, is that a violation?

That said I'm having trouble distinguishing a law against baggy jeans from a zoning ordinance that forbids you from painting your house fluorescent yellow. Both are arguably public nuisances, and that satisfies the RBT.

When it comes to open containers, a reasonable person knows at least what he is barred from doing, and such restrictions are generally applied to all individuals acting in a like manner. In this case, whether the ordinance is violated is dependent upon the wholly subjective view of law enforcement who are thereby granted plenary authority to decide what conduct is barred and what is not. That, James, is what is unconstitutional.