I once hunted what I thought was a scrape line because the scrapes were along the ridge, spaced maybe 50-75yds apart for almost 1/2mi. I thought for sure I'd set up 20yds off the side of the ridge and catch buck after buck coming down that row. Didn't happen like that at all. Set a camera up to see if they were doing it at night and caught nothing. I was perplexed but still kept hunting because something or someone was making those scrapes.
When I finally saw the culprit, it was eye opening. It was indeed a buck. A very big buck. And he was indeed making/refreshing the scrapes. But he wasn't doing it in a line and not all at once. He came up the side of the hill, scraped at the ridge peak, then continued on down the other side. He never traveled the ridge line at all, only crossed it. Furthermore, there were no obvious trails he was using. As far as I know it was just random spots. I'm sure he knew what he was doing, but he didn't bother to stop & explain it to me lol.
Anyway, from then on I don't hunt hunt "scrape lines" anymore because they are not what they seem. Since that learning experience I've paid closer attention to them and almost every time it's the same thing. They hit a single scrape from a perpendicular approach, then hit another scrape crossing back again, and so on. They don't actually hit scrape after scrape in a line like the evidence seems to suggest, or at least in my experience. They do hit every one of those scrapes, just not at the same time and not from the direction you'd think.