It's ridiculous to think that the PCs are some sort of mighty cosmic encounter attractors that cause multiple encounters a day to spontaneously happen where they are at the moment. Said encounters somehow don't happen anywhere else in the world. Rather, the PCs encounter so many creatures daily, because there are craptons of creatures all over the world and that's how many they encounter that day.
Or maybe because the PCs are in the wilderness where more monsters live? I don't run into many lions around here, but if I was exploring the Serengeti I think I might see one or two.
That leaves DMs who actually care about consistency to have to figure out how to fix the problem. Since there are so many dangerous creatures all over the world, there would have to be tons of adventurers all over the world to combat them. Of course, that can rub those who like PCs to be super special the wrong way. The only other way I can think of to keep things consistent without upping the adventurer population, is to lower the encounters that happen daily and thereby lower the deadliness around the world.
So it's interesting that you raise the point about consistency since that was my complaint about shifting rest schedules based on whether you were in a dungeon or the wilderness.
But I agree, you should be consistent. That is, if the PCs are wandering along a road between civilized areas, ensure that the number and types of encounters they are having would be the same type as a similar party. Which means, in my world, the PCs are
more likely to have an encounter, and it's probably going to be tougher than their regular encounter near a town or city.
I'm sure you'll question that. Here's why:
1) The wilderness is an area that has not only the mundane animals we have, in an abundance we're not accustomed to (check out the animal populations in North America pre-colonial times), but it's also a world where there are monsters and magic. So the wilderness is dangerous, and the farther you are from civilized areas, the more dangerous it is.
2) Because the wilderness is dangerous, the most common way to travel between civilized areas is by caravan. It's slow (no better than a slow walk) because of having to tend to beasts of burdens pulling heavy loads, but also because the people in such a caravan walk. Maybe 10 to 20 miles daily. The numbers are probably 30-60 people plus beasts and wagons. There's safety in numbers, with sellswords hired to protect them during the walk and the nights.
3) Predators and semi- to non-intelligent monsters avoid such large groups unless really desperate. That's the whole point of traveling by caravan, it reduces the risks.
4) Brigands, bandits, and attacks by intelligent monsters are in larger groups. They have to overcome the caravan, after all. But maybe 10-15 of those are combat capable in the caravan, and they realize that a group of 15-20 monsters/bandits is sufficient under the right circumstances.
5) Adventurers tend to travel in small parties. Not a large caravan. They
attract predators, non-, semi-, and intelligent monsters and brigands/bandits. Because those encounters may be against creatures that are prepared for attacking caravans, they are larger groups than they would encounter elsewhere. A group of 15-20 monsters/bandits ensures a reasonable amount of success against a caravan. Against 4 PCs it's likely to be a really tough encounter.
So yes, a party of PCs wandering through the wilderness are encounter attractors. And they happen anywhere else in the world 4 to 6 people decide to wander the wilderness that is infested by monsters and other evil things. The fact that PCs often go looking for trouble has an impact as well ("hey, look at that rubble over there, I wonder if there's anything of interest?" "Well, yes, says the DM, some undead..."). All of this is also assuming that the PCs don't have any enemies that might follow them into the wilderness.
To not encounter more creatures, and for them to not be more challenging would be inconsistent to me.