I think this solution also misses the fact that certain kinds of people (like bored kids) will walk through fire for a free quarter. It's not even the money, it's the novelty. So if you have a population of people who consider the charge 'the cost of shopping' and don't care enough about 25 cents to return the cart, you still have a whole other population of people who will hunt them down and return them for those people.
As a kid, I almost missed a flight while hunting luggage carts at the airport.
This class of products is room temperatures stable, and typeless, and it increases oxygen carrying capacity basically immediately. You can imagine how useful that would be for something like a Tour De France team. Keep a half dozen units of fake blood in your team bus. No special equipment. No rigorous temp control. You can give any unit to any one of your athletes without worrying about compatibility. You can administer it on race day, eliminating any chance of being caught in the runup to your event.
Obviously Biopure condemned off-label use of their product for blood doping, but behind closed doors they were super proud that it was seen as effective enough to be called out by name by WADA. No publicity is bad publicity and all that.
You can see my top-level comment for more context, but I've seen other products in this space called "oxygen therapeutics" for exactly this reason. They're not really blood, they're an oxygen delivery system. It seemed like a pedantic distinction when I first heard the term, but I think you make some good points about why the distinction is meaningful.
Biopure was a company doing something similar in the US. They imploded in the early 2000s, but they had created an "oxygen therapeutic" (blood substitute) by isolating hemoglobin based oxygen carrying molecules FROM COW BLOOD!
The fact that they weren't using whole red blood cells meant the product was typeless, room temp stable, and better at perfusing around arterial blockages and into tissue since the molecules were so small.
Unfortunately, the company was kind of a mess. They managed to get licensed for sale in South Africa, and in the US for the veterinary product, but never managed FDA approval. It's a shame. Everyone could see the promise of the product, and it really actually worked, but they just couldn't seem to make the business viable.
Edit: When I say they imploded, I really mean it. They got prosecuted for misleading statements to investors about the state of US clinical trials, and the legal proceedings became farcical.
"On March 11, 2009 [Senior VP] Howard Richman pleaded guilty in U.S. District Court and admitted he had instructed his lawyers to tell a judge he was gravely ill with colon cancer. He also admitted to posing as his doctor in a phone call with his lawyer so that she would tell the judge that his cancer had spread and that he was undergoing chemotherapy."
That guys was sentenced to 3 years in prison. Here's hoping this new blood substitute has a happier outcome!
I solved all of them. Minor nitpick: Since every criminal confesses to their crime, the fastest way to solve most of these is to query the confessions table for strings like '%i did%' or '%kill%'.
As a kid, I almost missed a flight while hunting luggage carts at the airport.