Were the victims hurt? Financially impacted? Emotionally scarred? Absolutely.
Whether its someone copy a work verbatim, someone lifting paragraphs or a page here and there from a book they are critiquing or beta reading or even direct from an ARC (Advance Reader Copy.)
It's a fairly murky world these days, that the bottom feeders (my term for plagiarists) inhabit.
As authors, it's important to protect ourselves and our Intellectual Property. (IP)
In the past it was sufficient (some said) to simply print the work out, place it in an envelope and mail it to yourself with the date stamp and leave it unopened. Now whether that was true or not, I cannot comment. (I'm not a solicitor or lawyer so any advice I can give is very general and you would need to get legal assistance to ensure you are on the right track.)
But, there are some simple things we can all do, starting now to begin the process of protecting yourself.
1. When you take on a new Beta Reader/Critique Partner/ARC reader send them the guidelines or a contract outlining their rights and responsibilities. Make it simple to read. (Yes, I do have one and have implemented this personally)
2. Love them or hate them the Macs rule. Religiously back your work up to your time machine. You now have a date stamped view of your computer at any point in time that can be used as evidence. And trust me, if it comes to that, your Time Machine will be your best friend!
3. Before sending anyone your precious work, check them out. Are they known for pirating work? Sharing ideas you've written? How well do you know them? Other friends in common who can vouch for them.
4. Don't be afraid to remind them from time to time of the agreement you requested they complete. Doing so may annoy the odd reader and if it does, they probably aren't the right fit for you. Those who will stick by will understand that your are protecting them as much as yourself. Educating your readers is in everyone's best interests.
Lastly, if all else fails, make sure to use the Peak Body you belong to (RWA - US or Aus, RWNZ, ALLi etc) as well as sufficiently trained and licensed legal assistance.
You wouldn't let someone walk in your door and steal your purse. Don't let them take your hard earned work.