I bet at the time it was all just one big wheeze - they were viewed as perks of the job, the recipients knew full well where they were coming from, and simply didn't want to question the gravy train. There were enough people who were prepared to block anyone who dared question it, so they all felt quite safe and happy to accept the freebies for services rendered to the SNP cult.
Swinney knows it was widespread - and he needs to keep the lid as tightly sealed as possible as a result. He may even have been a recipient of a freebie himself. Murrell is absolutely getting something in return for taking the blame - I just wonder what.