Credit card tips

I own a drive through coffee shop in Washington state. We are able to stay open. I’ve put in precautionary measures for the safety of my employees as well as my customers. One being we are not at this time handing out customers credit card slips to be signed to minimize germ spreading. The only reason we have people sign is to capture card tips. It is not required unless it’s over $50 to sign. So I’ve turned this feature off and because of it my employees are complaining. They all agree they are getting more in cash tips along with more hours due to high demand. I’ve had conversations with two of them about this and bottom line I’ve closed the conversation with if they are not receiving enough they are not by any means required to continue to work at my company that we all have to do what meets our needs. But I keep having looping thoughts. That I would never have expected this from any of them. All their spouses are still working. I don’t know what their financial needs are maybe they do need more. They are able to still work. It’s not just them that is feeling this. So please help. How can I clean up these thoughts?