I press them open unless I need a ditch there. There are really only 2 reasons for pressing to one side:
-to make a ditch to quilt in
-to spin certain types of seams

I know there are some who claim that pressing all to one side "makes the seam stronger" but I've never had an issue with my seams coming undone unless I've used too long of a stitch to secure them. I made plenty of kids' quilts with all the seams pressed open (the method Leah Day teaches) and have yet to have any issues with my seams. But whatever works for you is what you should do. I don't think it will make a huge difference one way or the other.

same for me... most instructions I have followed suggest pressing seams toward the border so I've just continued to do so.

I'm confused. There seems to be two different conversations going here. One is talking about the seam that is created when you sew a border to the quilt top. The other conversation is about the seam that is created when you don't have enough length of fabric for your border and need to sew two pieces together.

When I'm sewing my border on the quilt top I press to the border side because there is usually less bulk that way.

When I'm joining two pieces of fabric to get the length of fabric I need for the border I sew on the bias (45 degree), trim my seam and press open. The seam becomes nearly invisible that way. I do the same when joining for binding.

I think a lot of people are not understanding the "two fabrics, so you have one long strip of two fabrics". Are these two fabrics side by side or end to end? I think either way it wouldn't really matter which way the seam is pressed.
If I am making a patch when I run out of fabric and have to piece a corner with the same fabric, I make sure to press that seam open, so it will be a little less noticeable. But when joining different fabrics when you will see the seam anyway, it could be pressed to the dark or open; either way would be fine.