[stylin_geek]

Hmm, the law can be changed, but I don't think it could be enforced against the owner of this stand. A little something known as "ex post facto" would come into play, methinks.

[Phantom Lord]

ex post facto wouldn't apply as it protects one from prosecution for something that was done prior to it being illegal.

As an example in this case, say the law was changed and the penalty was a fine of $100 a day per violation. He could be fined for every day that the picture remained up after the law went into effect but could not be fined for days it was up prior to the law taking effect.