It is a crime, and as kid pointed out (in his endorsement for more business) it costs real money, paid for by taxpayers like you and I to fix/replace said signs. So, yeah, probably fines, possibly jail time if it gets really big. In this case, it looks pretty juvenal, so if the perp was a juvie the penalty would be somewhat less.

But yeah, it's also kind of funny, though not side splitting funny.

Was curious:
§ 28.03. CRIMINAL MISCHIEF.

(a) A person commits an offense if, without the effective consent of the owner:
(1) he intentionally or knowingly damages or destroys the tangible property[0] of the owner;
(2) he intentionally or knowingly tampers with the tangible property[0] of the owner and causes pecuniary loss or substantial inconvenience to the owner or a third person; or
(3) he intentionally or knowingly makes markings, including inscriptions, slogans, drawings, or paintings, on the tangible property[0] of the owner.
(b) Except as provided by Subsections (f) and (h), an offense under this section is:
(1) a Class C Misdemeanor if:
(A) the amount of pecuniary loss is less than $50; or
(B) except as provided in Subdivision (3)(A) or
(3)(B), it causes substantial inconvenience to others;
(2) a Class B misdemeanor if the amount of pecuniary loss is $50 or more but less than $500;
(3) a Class A misdemeanor if:
(A) the amount of pecuniary loss is:
(i) $500 or more but less than $1,500; or
(ii) less than $1,500 and the actor causes in whole or in part impairment or interruption of public communications, public transportation, public gas or power supply, or other public service, or causes to be diverted in whole, in part, or in any manner, including installation or removal of any device for any such purpose, any public communications or public gas or power supply; or
(B) the actor causes in whole or in part impairment or interruption of any public water supply, or causes to be diverted in whole, in part, or in any manner, including
installation or removal of any device for any such purpose, any public water supply, regardless of the amount of the pecuniary loss;
(4) a state jail Felony if the amount of pecuniary loss is:
(A) $1,500 or more but less than $20,000;
(B) less than $1,500, if the damaged or destroyed is a habitation and if the damage or is caused by a firearm or explosive weapon

It's interesting because, like I said, they're just stickers. But I've already seen some instances where instead of just pulling it off they sent somebody out to paint over it, which I'm sure increases the cost. And is really stupid.