Yes, I can. But, will be "clever"/"best practices" rating recalculated in this case (if somebody hack solution)? Mistakenly solution cannot be in the top.

What's about adding possibility for hacking another persons' solutions with own test cases? (like in Codeforces system). I often see a lot of submits, that obtains unreasoned solves working with existing tests. But these realisations probably will be crashed with other inputs... and it leads to disastrous results in the future during working with real code on real projects.

For example, let's see on the popular task "Playing with digits" (https://www.codewars.com/kata/playing-with-digits/solutions/csharp/all/best_practice ). That's enough to take two big numbers for input, that crash 95% of solutions with TimeLimit. Also a lot of resolves don't have a processing of illegal input params. As for me, critical input values should be a part of tests. And in such situations (when task creator didn't provide anything), other participants should be able to fix the omission.