Is the "I accept" Button usually enough?

Click-thru licences have been accepted so long as terms policies visible and no surprises. However privity of contract is modified by legislation, eg australia has laws against onerous terms of big companies being imposed against smaller and of course, certain consumer protection laws cannot be exempted. EU Data Protection Directive governs all privacy issues of their citizens including email address. Getting into trouble is a function of how outraged a user would be and their willingness to take it to authorities so perhaps a better question is whether you,re trying to do anything outside existing norms.