Spot and Cover

[Ovinomancer]

Felix, scrying would be next to useless in this situation. All you would get is a scene of the PC's walking though a forest. Trees, bushes, maybe a squirrel or two. Not exactly a great way to tell where they are. Forest kinda all look alike once you're actually in them.

As for the spot, toughie. The rules don't make a specific point of this, but I think that the circumstance bonus/penalty brought up by RigaMortis is a good solve. Be careful, though... it might lead to abuses when a character is actually tring to hide. "What do you mean I don't get a bonus for hiding behind the tree? I get a bonus if I just stand there right?!"

 

[Felix]

Scrying gives you enough information to allow you to make a safe Teleport. If you can teleport somewhere, I would think that you'd be savvy enough to be able to figure out where that location is.

Scry -> Fly -> Invisibility -> Teleport -> spy on the PCs -> Teleport home.

That's well within the abilities of a 7th level mage. This is of course assuming that the "BBEG" is actively looking for the PCs.

 

[Ovinomancer]

It only provides the ability to teleport to a location because you can SEE the location. It does not let you know where that destination is. You can blindly teleport anywhere you can describe (IE 100 miles north). Being able to teleport somewhere does not mean you know where that somewhere is.

 

[Felix]

When you teleport somewhere invisible and flying, you can generally fly up and see where you are in relation to other things. Mountains, rivers, castles, etc. Once you are there, you can see for yourself where you are. And incidently, about where the PCs are. Just because Scrying doesn't let you know the PCs are 50 miles north north-west of your lair Dreadfort Evilhammer doesn't stop you from finding that out through other means.

This is what I mean when I say savvy.

 

[Ovinomancer]

Ahh... missed the invis part. That would work. Savvy, too.

 

[dcollins]

What about if the characters are walking along the forest floor, minding their own business without a care in the world, and the BBEG comes along with his owl familiar looking for them. Let say the forest provides about 75% cover from the eyes of the owl, that is flying only 60 feet above them.

You should take a look at 3.0 DMG p. 59-60 for rules on spotting or missing encounters in the wilderness. I'll summarize:

- Owl has a chance to spot PCs in light forest at an encounter distance of ~100 ft (3d6x10 ft).
- Spot DC to do this is 20 (base 20, no modifiers from table 3-2). Probably easiest for the owl at dusk when it has a total +14 Spot bonus.
- If failed, there's a 50% chance the owl misses them entirely. Otherwise, it automatically spots them ~50 ft (half distance).

If the PCs were trying to hide (half movement, of course), then that Spot DC would have been 25 + any Hide skill bonus.