Police Controls When leaving

So i got a question for yall. Its my 2nd time LIR this year but unfortunately i can only attend the festival on Friday. I Wanna come early on Friday and leave on Saturday at like 16-17 (4-5PM). I will come and leave BY CAR!

Ive heard the controls when leaving are pretty strict. Do they only do alcohol Test or other drugs aswell?

So is it possible to do anything besides drinking alcohol (Not too much since i gotta be at 0,0 Alcohol in my blood when leaving) ?