It can definitely be hemorroids. A lot of people seem to have this issue and not notice having any of them, but they can be smaller, where you wouldn't notice. This or hard stools would probably be the more common reasons. If there is no pain and stools are normal, not overly hard or large, then I would probably think it would be hemorroids. They have products for this, although I don't think you would need them if there is no discomfort. I also notice that I sometimes have this happen from wiping too hard. I will notice blood on the toilet paper, but then might notice some when using the bathroom another time. Using wet cloths (the kind that toilet paper brands make and can be flushed) helps with that issue!