'You' instead of 'one' in scientific assay

Hallo,
spending a sunny bank holiday Monday indoors marking essays, I came across a wording which surprises me a bit (especially after some advice I was given here). Some students use phrases 'You can see', 'you may notice' etc instead of the - in my opinion more appropriate 'one can see', 'one notices' etc.
Although I appreciate that 'one' is not commonly used in spoken language (at least not by my students), I would expect to find it in written language, especially in an (mock) exam paper.
What do you think?
Best wishes,
Gunter