Well now there's no point of banning BSM users as you can do it with 1.7.2. So you can't be banned for just using the normal minecraft, right?
1.7.2 introduces a sprint bind key. This is very different to the mod BSM (Better Sprint Mod).
1.7.2:
This update allows players to bind a key to pres or hold down which will make the user sprint. If they press it once it is much like just double tapping 'w'. Yet, if they hold it down, they will continue to sprint even after running into a block.
BSM (Better Sprint Mod):
This mod basically allows you to tap a button once so that your sprint is always on. You do not have to hold one key down to continue to sprint. This mod also allows a user to sprint backwards and sideways. 1.7.2 does not.
As you can see they are two very different things, and obviously BSM is still a kickable offence. Players will need to either continue to double tap 'w' (Like me) or hold down their bind key. I highly doubt that the staff will allow BSM on MCSG. However, to answer your question. No. You can not be banned for using normal vanilla Minecraft.