The problem with saying "Paizo make a clear distinction between Arcane and Divine" is that they don't in their modules. That, and Use Magic Device appears to modify many of these arguments.
For instance, the last 1e Adventure Path (Tyrant's Grasp) doesn't appear to state if any of its scrolls are divine or arcane. Granted I may have missed one, but the second scroll type encountered is Burning Gaze which is both a druid spell and a sorcerer/wizard spell - so is it divine or arcane?
If this is a mistake, I would expect it only in the first few adventure paths, by the last I'd expect it to be sorted. That they haven't gives me the impression that's isn't as much of a hard, absolute rule as it first appears.
This leads to the following problem: The druid and the wizard both ask if they can use it. I have to say "sure" because Paizo haven't made it clear which one it is. Even worse, PRD on Use Magic Device says: "In addition, casting a spell from a scroll requires a minimum score (10 + spell level) in the appropriate ability" - so for the aforementioned Burning Gaze is that Wisdom (Druid), Charisma (Sorcerer), or Intelligence (Wizard)?
That ambiguity in both arcane/divine and ability then gives a foot in the door for questions like this one.
Then the wizard becomes a mystic theurge and quotes the PRD's "Use Magic Device lets you use a magic item as if you had the spell ability or class features of another class" and says "So that allows me to scribe a divine scroll, and use my max-ranked Use Magic Device to learn that spell as a wizard, right?"
It's hard to say "no" when Paizo have given every indication they don't care by never specifying if scrolls are divine or arcane, and Use Magic Device does appear to allow the cross-over.