No, I know people who get arrested for stuff like this years after the fact.

I wonder whether the statute of limitations applies to such things. I hope it does.

It'd be trespass and other crimes on federal properly, so 5 years, no?

How is it federal property? It's owned and operated by an independent quasi-governmental organization.

The bridge is classified as a national monument, which would protect it as federal property.

I can't seem to find a single thing online that supports your statement, either concerning the monument part or federal jurisdiction of the bridge.

Further, it does not appear on this list:

http://www.cr.nps.gov/archeology/sites/antiquities/Monuments...

I'm assuming you made an error.