Results from 1000 students
Shows we may assume students know more than they do

These students are a pre-med class who studied this reaction in organic chemistry at high school chemistry and half a semester of Year 1 organic chemistry.
This page from BestChoice Reports has the statistics are superimposed on the question.
This shows that ONLY
65% of students realised that the difference between the alkene and the alcohol was a water molecule.
65% of students chose the correct structure for the minor product of addition.