Crap happens, back in the stone age days, a mechanic kept gas in a one gallon silver can that pyrene cameI'm not sure you are right or wrong on the "oil" assumption, but I know from personal experience that at one time at Holland, both the window washer fluid and the engine anti freeze they were using were both the very same color of blue. Unknown to me, a mechanic at our home terminal put the blue engine anti freeze in the washer bottle. When i was about 100 miles out of St Louis on a 2 lane road, it got sloppy. I tried to use the wipers with washer fluid and immediately couldn't see anything. The engine anti freeze smeared the windshield so badly, I had to pull over to clean it off with a rag. Luckily a little Mom & Pop truck stop was only 2 miles down the road, where I pumped out all the bad stuff, called Central and put in 2 gal. of good stuff.
Dumb, but understandable mistake by the shop people, due the same color of both coming out of similar 50 gal drums.
If it WAS in fact oil, that sounds to be more than an honest mistake.
in, another guy filled my fire extinguisher with the wrong can.
I almost burned up a guys WC 22 White, trying to put out his emergency brake fire.
PS watch your Ps & Qs, Upnorth may be watching