Do you think there is a video with someone throwing nails on the track? No there isn't. No one is zooming the cameras on a lap car that is 4 laps down is going 30mph slower when the driver reaches in his glove compartment and grabs a few nails and thows them out of the window.
Nascar is aware of the problem and it tried to fix it in the past:
https://beyondtheflag.com/2015/07/21...water-bottles/