Well, being a PWM controlled TC, you're not supposed to be able to feel when its locked or not. However, being OBDII the TC is monitored, and if its supposed to be locked, and the computer detects that its not, the CEL should be lit.
Most of our stations are E10. I used to have one citgo station that sold 100% gas, which gave me an extra 2 mpg. In Wisconsin we don't have vapor recovery on any of our pumps, except in the areas in and around Milwaukee.