How do I stop people from paying for my food n the drive thru?

I was maybe 18-19 years old when I first heard a news story about people in this chain paying for others food at the drive thru.<br>I would occasionally see it here and there in real life but ti never happened to me.<br>Recently, I am getting it a lot.<br><br>Going through a tough time due to a job loss, so I have been frequenting a chain of restaurants that is very affordable.<br>Three times now, I either get my food for free, or sometimes even a partial discount.<br>I am not complaining, but this is getting weirder everyday.<br>Sometimes I don’t even know it til I drive off and realize they didn’t give me my total.<br>I have tried to work the system out with the worker on the intercom, and I can hear them talking to the person behind me over the speakers.<br>It is just weird that I have had 3 times in 3 weeks. <br>Is there a way to avoid this?<br>I am not complaining at all, but I just want to pay for my damn food.<br>Am I the only person this happens to?<br>How do I avoid this?