Help! Multiple meanings to 'milking parlour'?

Can anyone out there help an Engine Room regular? Roz has written in with the following query:

Recently my work supervisor asked me whether I knew what 'milking parlour' meant. She thinks it could be a euphemism for some sort of tax dodge or other criminal activity. We don't even use the term 'milking parlour/parlor' in Australia – it's a cow shed! I was wondering whether you and/or your readers would have any idea.

I haven't been unable to unearth anything except the obvious "shed or building specially equipped for milking cows" (OED Online). Nothing about tax dodges or criminal activities, anyway.

Udderly stuck...

Malapropisms: execrators

Roz has emailed us the following job advert which contains a "lovely malapropism":

Opportunities exist for skilled people to undertake roles within the Mining industry in Regional WA. Our company is currently seeking individuals who have the following abilities: Machine operation tickets such as Dump Trucks, Execrators, 992 Loaders, Drills Graders, Dozers and Water Karts with 6 wheels and also able to undertake a Manager or Supervisory role.

Roz adds: "For much of the day thereafter, I daydreamed about what it would be like to actually be paid for cursing mine sites..."

(We seem to be having a glut of malapropisms recently. For anyone not in the know, a malapropism is "the mistaken use of a word in place of a similar-sounding one" (OED). The term itself comes from the character Mrs Malaprop in an 18th-century play. Hence the title of Apus' blog post the other day...)