It is possible for there to be multiple modes of transmission, and there is good evidence to suggest droplet transmission plays a meaningful role in COVID sprea

It is possible for there to be multiple modes of transmission, and there is good evidence to suggest droplet transmission plays a meaningful role in COVID spread. How much it contributes versus airborne transmission may be debatable, but that doesn't mean taking preventative measures against droplet transmission is "dogma". Here is some discussion of evidence for droplet transmission https://jamanetwork.com/journals/jama/fullarticle/2768396 https://jamanetwork.com/journals/jama/fullarticle/2768396 I'm also not sure why you would assume staff have had more contacts. The people that were eating at indoor restaurants in the middle of the pandemic were unlikely the type to be limiting their contacts. Most case studies also checked for antibodies after the fact, not just active COVID testing, so prior immunity would have been detected.