That is terrible!
They should have put the red flag out if there was an actual obstruction on the track. Normally yellow flags are put out as cautionary, but it doesn't mean come off the throttle a whole lot...maybe dial it back 10%-20%. Red flag normally indicates something serious such as a down rider or bike on the track or in the way.
Wonder if the guy that saw the yellow thought to slow down...not that there was actual debris on the track.
2001 SP1 (sold)
2004 SP2 (properly stored)
2012 Ruckus (stolen)
2015 Grom (under construction)
Weyrauch pronounced (Y Rock)...Rock for short.