Why are tax disc holders so damn important to BMW drivers?

I do on average 25-30 windscreens a week, and BMW's, in a variety of models including Mini's, are popular, so I can do upto 10 a week... Why are they the ONLY brand owners to complain about about tax disc holders? I'd say a good 85-90% of tax disc holders tear/rip/lose the sticky, etc when replaced, so naturally I carry spare holders (Autoglass branded, we aren't gonna supply other branded ones naturally) so that the customer isn't inconvininced and can display their tax disc when the job is completed.

Everyone whose tax disc holder I replace is gratefull - except BMW/Mini drivers!

I did a Mini yesterday, I get a call this morning from my guy in the office saying the owner had been on the phone asking why she has a new tax disc holder. Naturally he explained to her why, but she is demanding having it back! Too late now, it ripped when I tried to remove it from the screen, so it's been binned. But she's compaining cos she don't have a Mini branded tax disc holder! FFS, GET A LIFE!!!!

1) it's a fucking tax disc holder!
2) You can get a free one from BMW if you pop in and ask
3) Whats the big fucking deal!?!?!?

I just don't get why BMW/Mini drivers feel a BMW dealer branded tax disc holder is so important!

Fair enough if it's a special one, say an XROC or RSOC branded holder, but I did a MINT and I mean MINT concours condition RS2000 the other day and his tax disc holder ripped, I gave him a new one, he said thank you. Simple!

DICKS