The neighbor's response puts me much more at ease:
My apologies for causing your concerns. I can assure you that I was not closer than 10 feet from either of your folks while I was there and that I work from home for the past several years. My husband does almost all of our shopping and my work requires us to do daily COVID questionnaire screening and temperature checks. I have also been screened for COVID recently when I went to give blood.
I am happy to mask next time I come there. It was just going to be a fresh produce "drop-off" last night, but it turned into a little (social distancing) visit, because they seemed so happy to see me.
This is also posted at https://elainegrey.dreamwidth.org/818669.html .