Therkel

I am confident you knew the answer already, otherwise you would not have posted this in the first place. Perhaps you had a glimpse of hope for an argument from someone that you could not come up with yourself to justify the morally (and legally) wrong decision of keeping the laptop.

It is interesting to me how different cultures are. Where I am from, such an 'over-formality' is what is considered rude. Also, like @AsteroidsWithWings, I am unsure whether you take extra offense to the relationship being a female addressing a male 'superior'.

"[...] to sit in the right ergonomic position to minimize stress[...]": There is also the possibility that all this hype around "sitting ergonomically correctly" might be bad advice. For what I know, ergonomics do not fully agree and neither do studies on the topic. See e.g. this Herman Miller article.