That's a valid question. I believe that such guests comprise (i) anyone who is viewing those parts of the forum which can be seen without logging in and (ii) the search engine spiders which crawl around the internet cataloging whatever they can see.
A bigger question is who / what comprised "Most Online Ever: 950 (January 23, 2020, 02:01:43 AM)". I have to wonder if someone thought it a good idea to try to crash our site using a botnet. In the past I've noted a surprising amount of website traffic from Ukraine and have blocked all access from Ukrainian web addresses as I reckon that such users are more likely to be mischief-makers than Halcrow pensioners.
