I've seen a lot of reporting on establishments adding cashier-protecting sneeze guards to checkout lines--but no scientific evidence that they help. The explanatory language is vague: The guards provide "extra reassurance," one retail executive told Reuters, while another told USA Todaythat they provide "peace of mind."
But if there's no evidence they help, they certainly can't hurt. And I suppose companies want to be seen as doing everything they can to protect people from COVID-19.
With no standardized form factor, there is a fair bit of design variety in these sneeze guards, which range from off-the-shelf solutions to custom made by companies, to let's-let-the-maintenance-guy-figure-something-out. If you've not ventured outside of your house recently, here's what they look like, and you'll note that the complexity of fabrication/installation varies:
The iSupply ones are my favorite, if I may have a favorite thing that may or may not provide effective protection. But like I said they can't hurt, and peace of mind is probably something people are craving these days.