Whenever I make a Timmie's run I'll usually text people asking them if they want somethingwhile iI'm in the drive through waiting to be served. Could I be charged for this? I'm pretty sure the ohta does not apply to parking lots, not sure if that extends to drivethroughs as well.
Short answer is no. Long answer is some roads within, lets say a large shopping area/mall, may have arrangements to be classified as a highway. Not that a drive thru line would have that type of classification, but if you're navigating through this type of area, be careful while you use the roads within.