Hm, not sure why my client didn't show this reply. Andrew Morton writes:
Risk: some (odd) userspace code will break. Fixable by manually chmodding it back again.
The only scenario I can construct in my head is that someone has built something to watch drop_caches for modification, but we already have the kmsg output for that.
Reward: very little. Is the reward worth the risk?
There is evidence that this has already caused confusion[0] for many, judging by the number of views and votes. I think the reward is higher than stated here, since it makes the intent and lack of persistent API in the API clearer, and less likely to cause confusion in future.
0: https://unix.stackexchange.com/q/17936/10762
