For adult porn the legal system doesn't really care if they are consenting or real. A special needs teacher called Jane Longhurst was murdered by a guy who enjoyed violent pornography, so now mere depictions of particularly dangerous (and soon non-consensual) sex are made illegal. You could literally have signed written consent proof but if it looks like rape then it lands you in legal trouble because it might turn you into a rapist murderer.
This system doesn't involve hashing, just blocking a blacklist of URLs. Digital forensics labs come across a lot of child porn in their daily work though so it isn't much of an ethical challenge to build a hashlist of illegal material.
Exactly this, voluntourism is an exchange of money for time spent experiencing a very different culture which you can tell other people about for a long time and also feel good while telling stories to kids or laying bricks. Oh and a week long safari according to the article.
There is very little that is altruistic about the practice and an altruistic option is not an option for most people who go on these trips. I don't know what cut of the $3000 the school in the article got, but if it wasn't enough then I'm sure they wouldn't invite a load of useless white kids around to set their construction back.
Actually none of it is being paid by the hospital and doctors, this settlement was with the county and city. According to another source
"Eckert still has pending suits against a deputy district attorney who signed off on the intrusive search warrant, the doctors who performed the search and the Gila Regional Medical Center, the facility that hosted the exams."