It was actually effective (among the group of people who do these things anyway - not sure if anyone else thought about intentionally getting beaten by the police to earn a hundred dollars).

Well, sort of.

The day before Lag B'Omer required the police to clear everyone off Mt Meron so the entire area could be cleaned and barriers placed appropriately in advance of the big event. Obviously some people refused to follow police orders and hunkered down instead of leaving. Some people were arrested/detained, including a "young avreich". This fellow sat in the prison (in Tzalmon Prison, because Tiberias prison was already full) for 2 days before being taken before a judge. The judge issued an order that this fellow cant be in the area of Meron for 30 days, and additionally would be subject to full house arrest for 5 days.

Upon receiving the verdict this fellow requested that the 5 days house arrest be changed to 5 days of full arrest in actual prison. Strange request but this avreich explained that 5 days of arrest would give him $500 from the group paying $100 per day for being arrested. He explained that he doesnt earn a decent living and this would be significant for him and his family.

The judge actually supported him without sending him to prison. She said that he should submit his claim even without going to prison because house arrest is considered legally fully as a regular arrest - they give house arrest when there is no concern of escape or danger, but it is fully considered as having been arrested. Because of that she did not send him to prison but kept it as house arrest.

source: Hamechadesh

I would like to hear the end of the story - did he get paid or not?  I am not even sure the house arrest might be the deciding factor, as it might be included as a good excuse to not pay, but he was arrested before Lag B'Omer, not while fighting the police at the event itself. I would like to know if they paid up or if he was just a patsy.