Vandal(s) Changing “STOP” Signs to Read “POOP”

Yup, some jokester in Portland is vandalizing stop signs to read “POOP” instead of “STOP”. Would it be a valid defense for either (1) running a stop sign or (2) defecating in public?

“…But Officer the sign clearly reads ‘POOP’.”

Fantastic photography of the POOP sign at the Portland Mercury. Bonus, it is right next to the Hung Far Low sign.