I don't know what qualifies something to be considered a landmark case, but this case sounds like it might be one.. This is the first time I am hearing of such an incident..

Basically, the State looked into an avreich who declared his status as "Torato Umanuto" - full-time Torah learning - yet every time they checked into him, they never found him in kollel. Rather, he was voluntarily running some girls school and was Director of the NGO.

The State imposed financial sanctions on the kollel this avreich was supposedly learning in, and sued the avreich. The State argued that the stipend paid to kollel people is is order to assist those people who really live the life of torato umanuto, where the focus of his entire life is his torah learning. The State therefore sued to receive back all the monies paid in stipends to this fellow - 7 years worth of stipends, totaling about 84,000NIS.

The avreich's response was that he was caught out of kollel on a spot check, but the rest of the time he was in kollel and they can't know otherwise.

The State responded to that saying they cannot be expected to attach a "personal bodyguard" to every person in kollel to track when he is there learning and when he is not. It should be enough for them to show via spot-checking a number of times that he was not in kollel, and from that it can reasonably be extrapolated that he regularly was not learning in the kollel.

The court accepted the States argument saying the State is not able to attach an investigator to each person who receives "havtachat hachnasa", and a reasonable sampling is enough for an investigation. The State proved that his lack of attendance was not a one-time thing or a chance encounter being caught out of kollel, rather he regularly was not in kollel.

The court decided the avreich would have to pay the State 84,000NIS to return all the stipends, and another 8000NIS in court costs.
source: NRG