Greate vs Ice Slick

[Kurald Galain]

The spell Grease (http://www.d20pfsrd.com/magic/all-spells/g/grease/) spells out that creatures in the area that don't move don't become flat-footed. The second-level Ice Slick (http://www.d20pfsrd.com/magic/all-spells/i/ice-slick/) lacks this language.

Does this make a difference? As in, is there a general rule in Pathfinder that standing on slippery terrain makes you flat-footed? Or is the extra text on Grease simply a reminder that wasn't technically needed?

I'd like to have a rules source on this, not just a "I thought that..." or "I would personally rule that..." Thanks!

[Eldonauran]

You are only considered flat-footed when you use the Acrobatics skill to cross narrow and/or uneven terrain, not a 'slippery surface'. A 'slippery surface' is merely something that requires or increases the DC of an acrobatics check. The Grease spell mentioning that a character is not considered flat-footed is unnecessary.