I've stopped snooping, I found it to be bad for me. I snooped her emails, her SMS's. I stopped doing it when I realized that I was doing it for the wrong reasons, that is, to try and anticipate or understand what was going on in her head. It was my raging codie need and also, totally inappropriate and an invasion of her privacy.
At one stage I was even documenting and photographing the empties strewn all over the house. I stopped doing that as well once my confidence grew about the legitimacy of my concerns about her drinking, and the small army of people who could back me up about my claims if I ever needed witnesses.
It's very very hard to "prove" anything if you have a very aware and functional alcoholic. If he or she knows not to drink drive, drinks in a way that only you know about the problem, covers tracks well etc you will spend a lot of time getting blank stares from people when you try and explain what's really going on.