Uh, maybe so the killer won't *kill someone again* on the trail?
I mean the only way to catch him (assuming it's a him) by secretly installing cameras is to get video of him stalking or murdering the next trail victim. I'm not comfortable with random trail-goers being collateral damage and I'm surprised anyone else would be.
Uh that's exactly the point. Why let it be known cameras are going up? That's only going to deter the killer to go WAY down the trail somewhere, but where? which way? We wouldn't know until someone else gets killed. And I'm sure no one here is comfortable with any one being collateral damage.
The killer is a killer no matter WHERE he is.
I do believe though the cameras are being put up so it makes people feel more safe being on the trails.