I drive a Dumptruck, yesterday I pulled in front of drive thru windows, walked up , like I do everywhere else, I was told we don't do walk up orders, I want to know why not, all the other McDonald's do it

https://www.quora.com/Why-can-you-not-walk-through-a-drive-through

Why do other surrounding McDonald's do it, cause they respect truck Drivers, we give up our lives so the people can get what they want and need , just to be told we can't serve you , That is Wrong, You cannot sugar coat ignorance, Go-ahead try, I will put the word out that I could not get a bite to eat because I drive a vehicle that doesn't fit in the drive thru, thanks MCDONALD'S