So let me get this straight, lets say I play in a re-buy/add on tourney....170 people get in, we are down to the last 20 and i'm in with my original BI then people know that I am bad?
No, They will take advantage during rebuy period. Assuming they are good enough to know you are using suboptimal strategy. Post addon, noone knows why your stack is the size it is (unless it's obv you skipped the addon)
I don't want too play marginal hands early and if it don't work out then just re-buy. I think that is a donk logic, I have played 3 re-buy/add-on tourneys in the last 5 days, 2 of them I cashed in and I never once re-bought (I did add-on in all.)
Usually in the early stages in these tourneys on Carbon all you have to do is play tight and wait till you have a good hand, and when you do just push all in and a donk will call with something weak. I think you have to wait till you get put out to re-buy in the Carbon tourneys, you can't just add your stack during the tourney. I don't know if you can just add to your stack in the middle of a tourney on a tourney on other sites like PS and Fultilt.
If your table is tight, then get it in good, gambling would be dumb. BUt not getting the immediate rebuy is truly an awful mistake.
Almost all sites let you purchase a single rebuy once you are below your initial start stack -as well as the double rebuy of you get felted. EDIT: During the initial rebuy period only, of course