Nope, because I've never seen or heard of it happening. I've heard of questionable practices, like taking some cool stuff, free hotel rooms, and whatnot, but straight up taking cash in exchange for a good score? Nope, never heard of it.
People often bring up IGN as a big offender. I would like to point out that other game reviewers gave Isolation glowing reviews, but IGN didn't even give it a six out of ten. So what's the logic here? IGN didn't get the proper bribe, so in turn they decided to trash the game? Or is it more likely that people happen to have different opinions than other people...?
As for games having DLC, I still don't get what the big deal is. Now, if you're talking about on-disc, locked DLC, then yeah I understand. But I recently saw a thread where the O.P. was complaining about the Dark Souls II DLC saying that it was cheap and a cash grab. Despite the fact that the DLC came out months after the release of the game. DLC is not a bad thing. How it's handled is what decides if it's bad.