Did you try going into the Plays.tv Preferences and disabling "Launch Plays.tv client when Windows starts"?
Just uninstall it.
In fact, I'm thinking of just uninstalling Ratpr. They didn't ask for permission to install Plays.TV. I don't want Plays.TV because I use a superior service; Xsplit / DxTory / Fraps / OBS....you know stuff that actually requires user input to start AND INSTALL.
....Ratpr has become Adware....
@Illutian - It was actually a bug we found after releasing the 1.9 update. We should have corrected this now. We apologize for the inconvenience.
I once disabled Play.TV the way you posted but after an update it turned on again and this option is nowhere to be found. I ended up uninstalling it.
@Kavalorn - Correct. As mentioned a bug kind of threw it back at some users (not everyone though). So we do apologize for that.