I was about to complain about an AP where a hidden creature targets the party by "quietly" using its spell-like ability, when I found this nugget in the PRD:
Spell-like abilities are magical and work just like spells (though they are not spells and so have no verbal, somatic, focus, or material components).
And yet they provoke attacks of opportunity.
So suppose my succubus is using her Dominate Person spell-like ability. It has no verbal nor somatic components, and yet she's doing something that makes it obvious she's casting. Or is she? Is the attack of opportunity just because she's focusing on her spell-like ability instead of defending herself?
It really rewrites a lot of the things I thought about Pathfinder if my shape-shifting mind dominators (succubi, aboleth, etc.) can just meander through town, taking over the minds of anyone they please without anyone noticing anything out of the ordinary about them. (Except their tendency to stop and stare at random people for 6 seconds at a time.)
Do spell-like abilities have ANY clues that they're being used? How do other people play it?