Nnnnope. Rek'Sai's true strength comes from punishing people who are overextended or otherwise caught out. She has incredible ganking potential so if you're playing against one and someone on your team pushes their lane, whether it's you or a teammate, it's not Rek'Sai's fault that you've overextended when they have a potent ganker on their team. If you don't know where she is, same with any jungler, you probably shouldn't be pushing too hard. Unless you've got eyes on her, assume she's everywhere. You should be constantly worried about where she might turn up.
Almost like she's some sort of underground super predator or something. But surely that wouldn't fit her thematically, right?
She's got some of the best ganks in League, made all the stronger after she gets a Stalker's Blade. And, just as an aside, I feel it necessary to point out that she can't hide from wards. The issue with a Rek'Sai comes when you don't have enough warning to keep her solid damage potential from becoming a problem. If you can see her coming you can pull back so that her teammates can't capitalize on her knockup and following Chilled Smite.
You're essentially serving yourself up on a platter otherwise and if there's anything we've learned about Void creatures it's that they're always hungry.
... but really though, has anyone noticed that? They all have something to do with eating, even Kog'Maw.