1: Hi Welcome.
2: There are 3 enemies, and each have a 25% chance to spot you every time they attempt. That means every round they get to try (read: every round you are there scouting) there is a 60.625% chance you are spotted. Since detection = death, and one round is the minimum type possible, it's clear to see that even under the best case scenario, in which the stealther has a bit of an advantage there is still a greater than even chance he is not coming back. Treantmonk fails a lot, but when he referred to the scout as "the Corpse" he was absolutely right. Would you prefer 5%? Fine, the detection chance per round is about 1 in 7. Now consider that it likely takes you more than one round to get in, look around, and get out and the only conclusion that can be drawn is that I am exactly right - you either throw the enemy straight off the RNG by having no chance to detect you, or you auto fail. If there's more than three enemies, that's even more chances to fail.
3: I'm sure the enemy won't get suspicious about any fog or smoke coming up out of nowhere. I'm sure they will never mow their lawn. At least pretend you are serious.
Ok, seriously, without CoP (because all I'm ever going to answer to that as a GM is "maybe"), how do you scout ALL THE FUCKING DAY with magic? Because that's just the time when not being able to can really fuck you up. For instance, sometimes even a high-level wizard will have to walk to places. Well... not necessarily walk, but, NOT teleport. And if just for the reason that he doesn't know yet where he's going.
And what is that awesome spell that automatically overcomes a mundane hide check? Or a mundane disguise check, maybe?
It's just like this: Every time when when I've played, and there was no scout, we were ambushed. Every time I've GMed, and the PCs didn't scout (well, they also didn't do other things, but considering there were often days of travelling involved, and the levels weren't that high, there wasn't that much they could do..) they were ambushed, too.
So, short of playing a Binder, how do you ALWAYS know what's on the road ahead of you?