My personal favorite is when the recovery trailer (for rescuing the broken kart) is parked in the infield somewhere, apparently for the convenience of the track staff. Really nasty thing to hit, full of sharp angles, etc.
It’s all about awareness folks. The good news is that every time I’ve seen something like this and pointed it out, something has been done, as usually the situation was created by someone who wasn’t thinking and once the error is pointed out to the staff–who are busy handling 1000 things–they go “crapp you’re right, thanks for noticing” and move the obstruction.
Or, you can keep your mouth shut and hope you aren’t the unlucky soul who hits it.