Hi @Joseph2423 Sorry that this has happened to you. What exactly defined an 'utter mess'.? Did they break any of your house rules? Did they have a party against your rules and it was obvious? Could you provide a little more context? Was this Doug who gave you a great review already thats gone public? And Doug seemed to have a very good profile history.
Generally speaking guests on the whole are very good, but you will get the occasional horrid booking.
I found I did have to be explicit with the Checkout rules (I had my own far before Airbnb implemented the list), but make sure you have a good list of checkout rules. Because then you can hold guests to account.
I ask that they tidy up, take garbage down to bins at gate, clean BBQ (which hardly ever happens so i just suck that up), return furniture to original location, wipe down kitchen (some do, some don't). I don't expect vacuuming or bathroom cleaning etc. If its OK but they haven't broken enough house rules, then i'll still give them 5, but i do say in comments 'Guest left house OK' which gives a hint to other hosts, they weren't immaculate (and only a small % ever are). If enough of my house rules were not adhered to, then i rate them 4 and say 'guests were polite and clearly enjoyed themselves. some minor issues in not adhering to cleanliness of house rules but otherwise ok'.
I had a look at your listing, what a wonderful place! The few things that immediately stood out for me though as a potential issue (and this is entirely personal) that might cause a different expectation of 'mess' is the spa, garage and lounge.
The Spa because, well its a maintenance thing and there's nothing to say, clean it, leave it as found, tidy up around it etc.
The garage because, well, so many wonderful things to use, but who is to say guests will put it back exactly as placed? They generally won't, if they use it! It will be haphazardly thrown back and that's their definition of done. Unless you label where you want everything to be put back, and then in house rules say, 'put everything back in garage where found' (which is a bit over the top tbh).
The lounge/chairs because they are white. I love white. But over time, surely guests are going to stain them, stand on them, spill something on them etc. Easy for a mess to occur there. Are they easy to clean?
Without understanding context of mess though, sometimes its incumbent on us to minimise the risk of 'mess' in the first place. Don't leave anything out that you don't want broken, or don't provide things that potentially can cause issues is my advice. And if we want the income but enjoy our holiday house, need to remember we are in the hospitality business and it's not really your home under those circumstances - it just a holiday property for guests. We need to change our own expectations especially if you maintain an immaculate home in the first place. You kinda need to suck up it in order for the income in my humble opinion. Can't have our cake and eat it too.. I feel like my guests fall into less than 10% that are troublesome, majority are ok to good, and remainder are absolutely perfect. Learning to filter out guests without good profiles also helps.
Kind regs
Hope this helps
MK