Welcome to our on line answers forums! To answer you question, you will not be able to view a different channel than what is being viewed on your set top box and if you do change the channel via the on line remote control, it will also change the channel at the Slingbox location. The Slingbox controls your set top box just as it would if you were at home watching TV. Also, only one person at a time can be streaming the Slingbox so if someone else was to log in why you were viewing, or if you were to log in while someone else was viewing, you would be prompted to disconnect the other user before you could connect. Please see the link below for further information and some alternet ways to hookup your Slingbox if this is an issue.
I hope this gives you a better understanding of how the Slingbox works and if you have any further questions, please feel free to reply.
Sling Media Moderation Team