It's not much, but we have seen in the past with the likes of Van Aert at Koksijde a couple of seasons ago. I don't see anything wrong with backtracking as a rule, however today was obviously a problem it can cause at therefore when doing so, one needs to take care when doing so. I feel what happened today was just that Kastelijn misjudged the speed/how close Verdonschot was and could even of happened if the backtracking rule wasn't in place (i.e a rider running round the course in the correct direction with a mechanical, attempts to move off the general racing line and is unseen by a fast approaching rider who is taking a different line or fans/trees/barriers block the view of the exit of the corner).Yes, backtracking is allowed between the two yellow flags on the pit lane.
So of course the rule is to blame to things like this. It must be expected that the riders are giving 110% and over they limits and cannot fully think on a situation like this. Allowing riders to reverse and go on the opposite direction of someone going 25 or 30 km/h is bound to result in disgrace. Even more in shitty pit lanes like the ones we had in Brussels, with trees on the middle of the race line and on the middle of the pit line. And if you ban backtracking completely, the amount of mechanicals happening on the pit lane must be like what, less than 1% of the total mechanicals for a year?