It's rough for independent song writers. Any meaningful success paints a massive target on your back. Tools like this could help, but only for as long as you can trust them. If this tool worked like domain name searches do, then Google would instantly copyright any melody you hum that didn't match over a certain percentage so that they could sue you later when you tried to use it.
Music copyright is a huge problem. Having just four notes in the same sequence can be enough to count as infringement (the so called "four note rule") but avoiding that won't save you. You could write a song that was completely different from someone else's song, and still get sued successfully for copyright infringement just because your song happened to be in same the genre!
Worse, if they don't sign their rights over to the RIAA, the cartel can just bankrupt an independent musician in the court system no matter how weak their case. It doesn't help that the Obama administration stacked the justice system with ex-RIAA lawyers and that courts have been willing to bend over backwards to the RIAA's increasing demands over the years.