If you are really lucky, you will be in a tournament with only one live player at your table -- you! This happened to me recently at a Cake Poker
freeroll. I was clicking my mouse to raise as fast as I could before any new players came to the table. There were over 800 in the tourney, and I was hanging in in 15th place for some time. I guess 14 people at other tables were faster at raising than me.
Anyway, after taking everyone's blinds and then the blinds of new sitouts who replaced the sitouts who finally busted , I got another person at the table. He, unfortunately ran into my set of Queens and doubled me up, putting me into first place.
To make a long story short, I finished in 5th place and won $338.80! So ... if you are at a table with all sitouts, you have a great opportunity to build a stack which can take you far into a tournament. However, if you have two or three players and the rest sitouts, play is very difficult (like Capt. Zigzag said) unless the other players are extremely passive and let you continually raise and scoop all the blinds.