The biggest worry for any live player is that on the internet, someone, somwhere can see your hole cards. Hell I advertise sites. Its crushing if it is true with a big site.
I did an investigation over the hole card thing a while back
http://pokeranon.com/seeing-tables-hole-cards.html
Now the only way this could happen if it is inhouse or someone screwing with his group of high stakes friends PC's