I know this scenario is going to be hard to describe in a test-question format, but bear with me a bit.
4th and 10. QB looks to throw, realizes there's nobody open, tucks the ball and start to run for the LTG. 8 yards down the field, he realizes he's not going to make it and dives forward. During the dive, he "extends the ball out" and it "slips from his hands" and bounces out of bounds 1 yard beyond the stake.
Here's the "you'd have to see it part" -- you're like 80% sure that was an intentional toss and not an "oops I dropped the ball!".
Would you flag it as an illegal forward pass or would you have to be 110% sure of the intent?
I was just thinking about this since this scenario would only apply with NFHS rules, as the ball would be returned to the spot of the fumble under NCAA and NFL rules.