He may protest.
I totally understand his point of view, but just picture, videos of protesters you've seen and think to yourself what they have achieved. You can think of Neturei Karta or other extremist, in the eyes of those praying outside you are most likely looked upon in that same way. Remember, many of them either dont seek halachik guidance or do and have received a pesak to do so. Why do you think they will listen to you?
How about finding out who these people are and call them by phone and try having a civil discussion explaining your point of view and see if they will listen.
I have tried nicely, not so nicely and very not nicely. This is the last resort after this mornings incursions on my property. I am well aware of what I can do legally. To equate my actions to Neturei Karta is laughable...but what you think of me is none of my business anyway.
They are in the main chasidim of a Rebbe who has not davened with a minyan for 4 weeks already...confirmed. The schizophrenia of chasidim disregarding the directives of their own rebbe and trying to be more frum than him is astonishing. If their own rebbe has no sway over them I doubt I will. But at least this psak is now available to them for consideration. If it saves one life or even one person from getting sick it was worth it all.
A healthy Gut Yom Tov to all!