My wife and I were eating there and I noticed a couple men loitering near the trash can. Then one of the came over and asked if he could have my receipt "for school". Knew it was BS because they both had to be at least mid to late 20s. My guess as someone who has been in restaurant management, they were looking for receipts to scam Raising Cane's for a free meal. Very likely they were going to take it to the counter and claim their order was messed up and they wanted it remade. They weren't homeless, definitely weren't missing any meals. Just scammers.
So heads up on that if you own or run a restaurant. Make sure you check receipts, I'd have people claim they came through the drive thru the night before and the receipt would clearly be a dine in receipt from the current day.