As far as I know, "lest" should always be used with subjunctive mood, yet I find the following sentence quite unnatural, though it satisfies the rule:
We should publish a critique on this method, lest it gain momentum.
Is this example correct? Personally, I find it very hard to read the sentence without automatically replacing "gain" with "gains". I've found a similar example with "anyone", which makes me think that my intuition fails me:
"Lest anyone forget, adolescence is purgatory" (Jon Pareles)