The bill uses a confusing mix of the terms "campus" and "premises" -
http://www.lrl.state.tx.us/scanned/84ccrs/sb0011.pdf" onclick="window.open(this.href);return false;
Regarding public colleges:
The president may establish rules regarding carry "on the
campus of the institution or
on premises located on the campus", and the school must post 30.06 "with respect to any portion of a
premises" [411.2031 (d-1)] To me this says that the school can prohibit carry anywhere on campus (including in a private car in a parking lot) but only has to post 30.06 on premises (i.e. buildings).
Additionally, a license holder commits an offense if he carries on "a portion of a
premises". [46.035 (a-3)] So while the school can prohibit carry anywhere on campus, it's only a crime if you carry into a posted building. For example, if you carry in a prohibited parking lot and get caught, you could be not be arrested but could still be expelled.
Personally, I don't see this as a step backwards. Under current law, a school can prohibit carry anywhere on campus and punish anyone who violates the prohibition (expulsion, etc.) SB11 would not change that. Under current law, it's a crime to carry into any building on any campus. Under SB11, it would be legal by default and would only be a crime if the school has declared the building off-limits and posted it accordingly.