using camera height as a theft deterrent has some drawbacks, too.
A camera low to the ground might wind up capturing images of pretty small animals. I have pics of mice on trail cams! Also turtles, snakes, all sorts of stuff. Put the camera up high and you’re going to lose some sensor sensitivity. And you’ll have to angle the camera much more downwards.
A strong downward angle does have some benefits of its own, too. The sun is probably going to be less likely to accidentally trigger your camera, or wash out the images from glare if it’s triggered by something interesting at the wrong time of day.
My own use of trail cameras typically has involved downloading images and moving the cameras after a couple weeks, unless I have them on my own property, or on someone else’s property who has given me permission to place them there. I don’t visit them in-between, so it’s not like I’m beating in an obvious trail to my cameras. Watching where you place them otherwise, and avoiding trails, utility ROWs, fencerows, etc is smart. I’ve had some really excellent results aiming cameras at trees laying on the ground. Sometimes you can’t much get around these challenges. Try setting up trail cams in a prairie with no trees sometime. You either use existing fence posts, or you set your own posts for the cameras. And the cameras are REALLY obvious. Needs must sometimes.
I’ve never been so strict with separating observations as saying only 1 per day, either. I like using a 3 shot burst from my cameras when they’re activated. That way, if the camera makes a sound, or the IR flash isn’t actually no-glow and the animal stops to look at the camera, I’ll get at least one other shot of it. I’ve also tended to use a decent delay setting on the camera after each burst to let the animal clear the area. So I look at timestamps to help me decide if I’ve seen another animal, in addition to markings.
For occupancy type studies, all that matters is that there is ANY observation of a species at a site within a given day. More observations than one don’t matter. For those kinds of studies, you’re not going to mess up someone’s study by including more observations if you think they’re distinct.
For some studies, repeat obs do matter, but usually for those, individual animal IDs are important. So identifiable markings or tags are necessary.
Personally, I’d rather err on more observations than fewer. If someone does happen to be an expert at identifying individuals of whatever species from photographs, they can sort through them to decide if it’s just one individual observed multiple times or whether they are distinct observations of different individuals. Unless it’s REALLY obvious, I’m not that expert, though I may know enough that I can tease it out for some species.