No they don't...in Oz,that would get you jail time.
I worked in a shell service station on a crossroads in the 80s. Very same intersection, there was our Shell, a Caltex, a BP, and an off brand "Total".
Part of my job was to watch the signs, see the changes, and report to management, who would tell me to change the prices, usually to the same as the main brands, and 0.1c/l higher than the Total...if it took an hour, I was in trouble.