Wouldn't that have made Snoke extra-cautious though? And to be fair, the first time he was drank, this time he wasn't.
This is, of course, assuming that Snoke is Plagueis in the first place, which the movie didn't confirm or deny (bar the music trolling).
Also, why on Earth, Snoke wanted Rey killed? It made no sense from the movie point of view, and if we go with Snoke = Plagueis theory, then from Plagueis book, he was arguably the most benevolent Sith lord in the history. Obviously, he was okay with killing things (he ordered Palps to kill his family), but the kill should serve some purpose, which didn't in Rey's case. Ren was already converted, and he had past his test by killing Han. Killing Rey was totally needless, while converting her would have served their purpose better (Plagueis wasn't a believer of the rule of two, so no problem on keeping two apprentices).