Joseph Berger, "Modesty in Ultra-Orthodox Brooklyn Is Enforced by Secret Squads", NYT 1/29/2013 (emphasis added):
“We give out proclamations,” said Rabbi Yitzchok Glick, its executive director. “We don’t enforce. It’s like people can decide to keep Shabbos or not. If someone wants to turn on the light on Shabbos, we cannot put him in jail for that.”
But Hasidim interviewed said squads of enforcers did exist in wildcat form.
“There are quite a few men, especially in Williamsburg, who consider themselves Gut’s polizei,” said Yosef Rapaport, a Hasidic journalist, using the words for “God’s police.” “It’s somebody who is a busybody, and they’re quite a few of them — zealots who take it upon themselves and they just enforce. They’re considered crazy, but people don’t want to confront them.”
About the expression "in wildcat form", AMG asks:
I have never heard of this expression and when I Googled it, I only found the football term "wildcat formation" but no references that seem to indicate that this term has entered popular (e.g., non-football) culture. Have you heard of it? Do you know what it means? It seems odd to use such an obscure phrase in a NYTimes article.
The OED notes that wildcat was figuratively
Applied to banks in the western United States which, before the passing of the National Bank Act of 1863, fraudulently issued notes with little or no capital, or to their notes or transactions; hence extended to unsound or risky business enterprises generally; also to illicit businesses or their products (e.g. wild-cat whisky); and more widely to reckless, rash, or extravagant undertakings, statements, etc., and (colloq.) with reference to wildcat strikes. This application is said to have arisen from the fact that the notes of a bank in Michigan bore the device of a panther, locally known by the name ‘wild cat’.
Among the cited contexts are "An exploratory oil-well, drilled where there is only a possibility of success", "Illicitly distilled whisky", "a sudden and unofficial strike", "an extra train running in addition to those on the timetable".
And Wikipedia tells us that a wildcat cartridge is "a custom cartridge for which ammunition and firearms are not mass produced". The wildcat formation is indeed an offensive scheme in American football, characterized by "a direct snap to the running back and an unbalanced offensive line"; but this usage is only about 15 years old, whereas wildcat banks date to the 1830s, wildcat oil drilling to the 1870s, wildcat whisky to the 1880s, and wildcat strikes to the 1930s.
So squads of enforcers "in wildcat form" would be unofficial, irregular, and illicit, and perhaps also reckless, rash, and extravagant.