That's not the norm, as of this year the chips are not commonplace in US-issued cards.
What you have is an imprint machine, where the merchant sticks your card over a paper with a carbon copy, slides over the top to make an imprint, then hands the piece of paper back to you for signature, then rips out the top page for himself while handing you the carbon copy one.
As you can imagine, this does not go well in food truck environment, where the mode of operation at crunch time might be "process as many customers per minute as you can".
Wow. That's just crazy! I haven't seen one of those imprint machines in 15 years. I thought they were completely dead. Even before the Chip cards, it was normal to have portable terminals that you would just swipe, enter your tip, and it prints the receipt that you signed.
What you have is an imprint machine, where the merchant sticks your card over a paper with a carbon copy, slides over the top to make an imprint, then hands the piece of paper back to you for signature, then rips out the top page for himself while handing you the carbon copy one.
As you can imagine, this does not go well in food truck environment, where the mode of operation at crunch time might be "process as many customers per minute as you can".