The other side of all this is that because so many schools are in financial trouble at the best of times (sailing close to the wind is the norm rather than the exception in GA related businesses of all types - there is something which attracts the Humphrey Bogart / DC3 / Casablanca romantic cowboys) it could be pretty hard for a GA business to successfully sue for defamation etc.
So many of them have been sued multiple times for non-payment (I mean County Court judgements, bailiffs dropping by, etc) and since this stuff is in the public domain (it gets contemporaneously published in the London Gazette or something like that, as well as ending up on many company data databases) the company would be hard pushed to make itself look like a pillar of financial stability.
Therefore, legal threats and related bluster and general crude playground type bully tactics are common in this business but rarely go further.
It is also pretty normal for customers to threaten litigation. I know of one UK aircraft dealer who has barely a single customer from the last decade who never threatened to sue at some stage. Pretty sad really, and the upshot of it was that the company didn't give a t0ss about anything anymore.