Except the non-Fluke devices don't have FLUKE across the front of the device, nor across the back of the yellow case.

Most people glancing at it are going to see a multimeter, not a fluke. They would look for some kind of Fluke branding, and a yellow bezel with grey front plate is not that, for signs of flukeness.

Especially in the red sparkfun card it is pretty clear that these are not fluke. I find it hard to understand that anyone would think this is a fluke device with even cursory inspection.

Edit: your google images link is interesting. It shows some fluke devices being in red, not yellow, cases / bezels.

Removing the word fluke from the search terms returns many devices that are either all yellow, or all grey, with a few other colours, and some that are grey in a yellow case. Many of the grey and yellow devices are not fluke devices.

It'd be interesting to see how many devices were using dark grey in yellow before 2000.