What are common mistakes made by Japanese kombini employees speaking "manual keigo" (バイト敬語)


Mainly inspired by [this question on what seems to be the misuse of a standard
idiom by a Japanese
employee](https://japanese.stackexchange.com/questions/798/usage-of-chdo/), I
was reminded of being told about バイト敬{けい}語{ご} ("manual keigo") in the past: a
slightly dumbed-down sonkeigo crash course handed to new kombini recruits,
that covers the basics but often results in widespread misuse of proper keigo
forms at the hands of young Japanese unused to this level of speech.

I know there were a couple very specific examples of classic mistakes
(generally: confusions between sonkeigo and kenjôgo).
[Wikipedia](http://ja.wikipedia.org/wiki/%E3%83%90%E3%82%A4%E3%83%88%E6%95%AC%E8%AA%9E)
([en](http://en.wikipedia.org/wiki/Manual_keigo)) lists a few disputed forms
(「おつぎのお客{きゃく}様{さま}」,「〜になります」...) present in the manuals themselves...

I'd be interested to hear if anybody has other examples of egregious misuse
and why they are not correct.




Using ～から like １万円 **から** お預かりします, which seems to be grammatically incorrect.

