[Adder]

Why are they being subjected to this survey at all? They are in school to get an education, not to enable some researcher to spend grant money. They are captive guinea pigs, under pressure to participate irregardless of the opt-out proviso. Re your smoking and drinking surveys, yes those would be objectionable for the same reason. Schools are not little social labs for the jollies of researchers.
Besides, behavior can be influenced by these surveys: its pretty easy to construct questions that reflect negatively on behavior... some about racial attitudes or drinking or smoking.

[Chemist_Geek]

in loco parentis, or does anyone recognize that doctrine anymore?