There is no where in RAW that I've found that supports that. It's not in Sneak Attack, not in Stealth, not in Flatfooted(Combat or Condition). All Stealth does is keep you hidden from the enemy, it no longer enables sneak attack. I was quite disappointed to learn that when building a crossbow sniper for another campaign.<br/><br/>If it did there would be a similar line as the following example in one of the relevant rules sections:<br/><br/>If a creature is unaware of you, they are denied their dex bonus to AC(whether or not they actually have a dex bonus).<br/><br/>or<br/><br/>If you have successfuly used the stealth skill to hide from a creature, they are denied their dex bonus to AC(whether or not they actually have a dex donus).<br/><br/><br/><br/>I'm not sure the reasoning behind it being allowed in your previous campaigns, maybe the specific DM house-ruled it, maybe it was forgotten/overlooked. It is one of the changes from 3.5 to Pathfinder that is easy to overlook/forget.<br/><br/>I am only pointing out RAW(Rules as Written).