Sorry, but that is nonsense - this idea that financial misdemeanors should never incur sporting sanctions, because they are 'different' things. They are not.
If a club has for example £1 million left in their wage budget to sign one more player, then they can afford a player on about £20k/week...
Kevin Nolan did, but its almost certainly not relevant anyway - the French links suggest that the two clubs are individually under investigation - ie entirely separate cases.
Not sure you can assume that, from that statement.
'Income tax and national insurance fraud' could mean paying undeclared wages (through whatever snidey 'image rights / offshore scheme / whatever, rather than brown paper bags) - basically what Swindon got demoted for.
(the authorities won't...