@Simon there's only really two ways to deal with it... either embrace it and be fine with people literally stealing from you on a daily basis, telling yourself it's additional exposure, or get bitter and start hating people who are otherwise just listening to your music
and well... the latter introduces negativity into the creative process
after such action, the same people know you but dislike you, and the others now know you as that asshole that sued people for listening on <site/service>
in all fairness though, if you're going to go after people for downloading your music while having it hosted and available on spotify, you're a hypocrite
yes, in the same way that if I mugged you and left you with all of the receipts so you could claim the tax back on those purchases you recently made, I left you with some money
