The type of company you're thinking of would insist it's engaged in tax avoidance not evasion, and since the UK has a General Anti-Avoidance Rule it would furthermore claim that the tax efficiency is a result of some otherwise quite reasonable behaviour and isn't some scheme that makes no sense except for how it conveniently avoids taxation. But mostly, as you hint, it's hoping to stay under the radar so nobody asks awkward questions.

However my point applies for shady outfits advertising on Google too. It may make sense for some companies to pay money to have a third party place their advertising, perhaps as part of some value-added service that offsets the extra cost, but under a know-your-customer regime that company doesn't want to annoy Google. If you earn $10M a year re-selling Google's adverts then the chance to earn $1M putting your name on an obvious scam is a bad deal - Google's going to cut you off and there goes the $10M pa revenue.

So the first type of shell is likely to get implicated in scummy stuff that happens in future, and as I showed you'll find out it's a dead end because your government doesn't care about making businesses tell the truth about who they are. And that's not Google's fault, it's something your elected representatives might fix if they thought you knew and cared.