Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
Since I don't want to ruin the thread any further: I tested Spirit Shackle when I made my first response to you ensuring that it was, in fact, just a rumor. Spirit Shackle only traps when its users remains active on the field.