As far as scrape activity I did find an article on that.
They did a 2 year study in Georgia on natural scrapes and found that 85% of the scrape activity was at night.
Here's the quote:
Study Results
The results obtained from this two–year study were surprising. First, we found that 85 percent of all scraping activity occurred at night (Fig. 1). This was true for both the scrapes along the field edges and those in the forest interior. White–tailed deer are typically considered “crepuscular” or most active during early morning and late evening. However, as you can tell by the graph, bucks are active throughout the night with very little scrape use during daylight hours.
So the fact that the bucks visited my mock scrape at night would seem completely normal. You are fooling yourself if you are planning on hunting a scrape line looking for a big buck to use it during the day, even during the rut.
Scrape sites are great for getting different bucks on camera though, they had 1 scrape that they monitored that was used by 13 different bucks.
Here's the entire article -
http://www.qdma.org/articles/details.asp?id=8