In the example given, the starting word is the simple two syllable word concise, with its common prefix. Ten people on acid or pot could take a round, and as long as the last guy says a "con" word, it doesn't matter if anybody guessed the interim hidden words. The only way to play accurately would be for everybody to write each hidden word for later scoring, and if you're stoned fat chance that's gonna happen.

But if you have a smart ass in the crowd, and in one of the early rounds uses the second syllable -ise/-ite/-act/-tion to craft his hidden word, then uses a "definition, characterization, or synonym" of that, it should fall apart right quick.

(Somebody could luck out in an interim round and get back in the groove.)