I agree. My DH has cancer and is immuno-compromised. I started saying "no" to tradesmen using our loo in the aftermath of Covid, when there was genuine reason and people were used to there not being a "free for all". I still do it.
If someone is here for a quick job, i.e. boiler service, or carpet fitting, I tell them where the nearest public loo is, the moment they walk in the door, so they are under no illusions, and can "plan" if they think they're going to need the loo, rather than end up desperate. There are a few options, all within a few minutes drive of our house, so it's not as if they have to drive miles.
For longer jobs, i.e. a kitchen fitting, external decorating, etc., when they come to quote, I tell them to include a portaloo in the quote. They're pretty cheap really for daily hire.
We had a few awful instances in the past - one neanderthal workman used our towel to wipe his arse, so it was covered in shit. Another actually stood on our loo seat in muddy/oily boots leaving marks/stains I couldn't remove. And another left bits of shit on the wall beside the loo and all over the floor. Some of them are barely better than animals. A bit of wee sprinkling sounds tame by comparison. These guys weren't "cheap and nasty" workers either, they were local/reputable firms that were well known.
We've had 40 years of living in our house, so although such disgusting events don't happen often, we've been here so long, and had so much done (3 new bathrooms, 2 new kitchens, outside decorating 3 or 4 times, new roof, central heating replaced, re-wiring, etc etc), that we've had a lot of workmen in the house over many years.