The article says that Monum's leadership didn't want to publicise the repair, but why would they? It would be a tacit admission that illegal entry into protected historical sites is justifiable for the purpose of 'guerilla restoration' - wherever such a position is valid or not, endorsing it would indeed compromise Monum and similar organisations. Monsieur Jeannot was surely right in this regard.
That leaves me wondering why simply asking wasn't an option. Are Monum really so resistant to offers of restoration that a few phone calls and a press release couldn't have done the job, saving both sides a lawsuit?
I suspect that would simply take all the fun out of it. So, Monum's stance is definitely valid, as is, in this particular case, at least, UnterGunther's.
And the less is spoken of the guerilla gorilla Jesus [0], the better.
[0] https://news.artnet.com/art-world/botched-restoration-of-jes...
And as for that Botched restauration I think the less politically correct term for it was "monkey with down syndrome" at the time. :)
In the year following the failed restoration, tourist activity generated 40,000 visits and more than €50,000 for a local charity
Using skill and irreverence for the common good, making the restoration basically a piece of performance art in itself.
I'd buy the UnterGünthers a beer.
A man created a "fake" highway sign in LA because he saw how confused the lack of signage made motorists, and it took a long time for anyone to tell it wasn't actually real.
His observation that if you look the part, you can get away with just about anything matches my experience, though - when in university, the students' union I belonged to had all sorts of hi-vis vests and hard-hats which were used if we had planned any shenanigans - worked every time.
You'll get farther with a hi-vis vest with a reasonable logo on it and a smile than with a smile alone. Bonus points if you also carry a clipboard and a VHF radio.
https://news.ycombinator.com/item?id=39977574
Quite likely that OP found it, and decided to submit it, based on that comment.