Tax officials may well not be very efficient but computers are! I know of one case going to Court because someone who always paid cash was greedy for his loyalty points and so the Tax Officials proved just his supermarket purchases were greater than his declared Income. I guess his Merc didn’t help much either!
I can also confirm that the Authorities, Tax included, crawl thousands of sites and forums automatically and officials manually look at ones of interest to them,
I think a lot of you are just scaremongering, the tax officials aren’t that efficient. If you sell a house here just buy one in the Uk and transfer the money over for a direct sale. As for tax officers reading forums, get real…just how many forums are there?? They would need a whole department.