On the topic of whether masks have made shops more or less busy, I've downloaded the google mobility report data and had a look. It seems to have had a negligible (/slightly negative) effect on grocery shopping, but more generic retail & other recreation locations have seen a marked increase. How much of this is down to masks encouraging people, or just simply more of these locations opening up, I couldn't say, although it does seem that it was on an upwards trajectory before the introduction of masks.