Precedent
HMRC goes after government entities, dragging them through the courts, imposing fines and fines are paid.
When it comes to private companies, precedent is already set and courts have things to refer to therefore increasing the likelihood of a result for HMRC.
If your a medium or large business with that liability then you should be worried.
They will go for the big ones first, even if HMRC lose they still win as it scares people into compliance.