I think it's definitely harder than we think; when I think back to how I was like before becoming phobic, I'm shocked that I managed to never get sick - I mean I worked a cash register in a store, and half of the time I'd forget to wash my hands before eating! I rode transit all the time, ate on buses, sat in crowded lecture halls, ate in university cafeterias, etc etc., even rode the trains around through Europe and haven't heard of sanitizer! And yet the one time I ever got noro was at home from DH who got it first, and I didn't realize and thought he just ate something bad. And even then we managed to keep 1 yo. DS from picking it up. So given all that, I think it's not that easy to get it - yet knowing all that, once the switch in my brain has been flipped, I now freak out if I eat a sample at the store after touching the cart...I KNOW the chances are so slim, yet I'm terrified of having it again.