A little trademark thought-experiment: under a proposed UN treaty, Internet Service Providers (as well as search engines, social media sites, online auctions, online games, and sites like Etsy and Thingiverse) will be responsible for detecting and interdicting trademark infringement and helping punish infringers by retaining and providing their personal information on demand from a trademark holder, without a court order.
Now, many coffee shops today are ISPs (that is, one of the kinds of intermediary targetted by this proposal). And many coffee shops today are the locus of trademark infringement -- say, when you walk in with your kid clutching a fake Barbie from a stalls market or a blanket in Santee Alley or on Broadway. If you applied this intermediary liability standard to the real world, every barista would have to be on the lookout for this kind of trademark infringement. If someone in the shop were to say, "Hey, I work for Mattel, and that Barbie's a fake!" it would be the barista's duty to leap over the counter and take away the fake Barbie.
But her responsibility wouldn't stop there: her employer would have to set up cameras and cash-register logs so that they could identify infringers later. So after you left with your kid (who is by now in tears, screaming for her lost Barbie) (or "Barbie") the barista would have to pull your name off your credit card receipt and hand it over to the random dude who says he works for Mattel, without seeing any ID (much less a court order). And she'd have to print out the photos and turn them over too.
Or she could refuse -- but if she's wrong and the Mattel guy is right, well, her boss will be on the hook for the trademark infringement, too. The barista had better be some trademark expert if she plans on refusing the request.
Many institutions are "intermediaries" for bad acts: kids ride the subway to parties where they drink before they're legally allowed to; is it the transit authority's job to police alcohol laws? Cruel pet owners hit their dogs with rolled up newspapers; adulterers meet in hotels; fraudsters use telephones, pens, photocopiers and envelopes. All these criminal acts are not subject to policing by intermediaries -- why should one industry's civil actions be the entire world's responsibility?