I'm not on LinkedIn but I got a message from an old friend along the lines "Hi, I'm Dave and I've joined LinkedIn......". He didn't deliberately send it though, it was done sort of automatically by LinkedIn when he joined (like you, at the behest of his employer).
My point is that she probably didn't deliberately target of contact you - it was an automated thing most like. How their system Hoover's up her contacts I've no idea...... Maybe there was no direct link? Maybe it just put you together as two professionals who have something in common like location, interests, age or something? Still a bit disconcerting though I grant you.