It's illegal, and if you're caught you can be sued for millions of dollars. I'm no lawyer, but I think the maximum penalty for copyright violation is $150,000 per violation in the US. Even "borrowing" 10 books with your plan could land you with enough fines to wipe out your home (if you own one) and all your savings. It's one of those things where the chances of getting caught are small, but the consequences of getting caught are commensurately massive.
Are there any laws against illegal downloading? And, how is the average person supposed to know if Apple/Amazon/etc.. are legally allowed to distribute the content they are selling you?
Note that its hardly illegal to borrow from a federated library or do an inter-library loan using p-books.
Also lets confuse the issue. Lets say the shady .ru site is in fact a perfectly legal genuine gov't supported library, although "everyone knows" this branch specializes in inter-library xfers and loaning out ebooks to mostly foreigners. This is going to be a complete mess to enforce and is not illegal in any way.
And realize any attempt to close this "loophole" is going to totally screw up foreign exchange students. Thats another excellent loophole, lets say I am now a official, govt sponsored and fully legally documented online student of the university of Elbonia, eligible for all manner of shared ebooks from the official perfectly legal and govt sponsored U. of Elbonia library.
Also I'm unaware of any recent "headline grade" prosecutions for downloading. Uploading, sure. I'm not offering to loan my ebook copy of Red Storm Rising to someone in .ru, I'm borrowing his copy. He's the one violating a copyright, assuming he is in fact violating any copyright.
I have no idea why I can't borrow an e-book from a shady .ru site on the internet if I want. Or a perfectly legit site in the .uk
Therefore there seems little reason to charge my physically local library an enormous amount of money other than to encourage piracy in order to discredit ebooks as a technology. Perhaps an alternative plan is to get local libraries out of the e-book business and keep e-books online (presumably tightly centrally controlled)
My local library used to do books, but now its a downscale free internet cafe, complete with vending machine coffee, along with being a homeless shelter and free day care operator. I think they still have about half their books. But in a business that's pivoted almost completely out of books and into daycare and related areas, I don't think the price of books really matters anymore.