This is our first crack at hosting an underhanded contest, so if this turns out to be a problem in practice we'll happily take this into account for next year. :) erickt is the one who came up with the specific challenge here, and I believe part of his motivation was to test not only the constructs of the language itself, but also to probe for the sort of exploitable bugs that may exist in real Rust codebases in the wild, e.g. web frameworks, in order to determine if tweaks to the language or stdlib would feasibly render such exploits toothless.