Weekend commits are actually less likely to introduce vulnerabilities, but they take 45% longer to fix.
I can only think of contributors being nice and relaxed, doing their most brilliant work. Work that is a bit too brilliant for the same contributor to fix any bugs found during any other conditions.
insert that one quote about being too smart for one's own good
Edit: Weekend commits are 8% less likely to have bugs, but those bugs take 45% longer to fix! This site is gold.
Edit 2: that may not mean what it looks like at first blush.
The scroll at the top of the page sometimes changes, and "hold shift to draw" is one of them. Shift-C to clear.