A single player going to check it out? Yes, 100% inadvisable. Don't do it. Even if there are two or three of you, just don't; it's not worth the risk.
However, if your whole team is in the vicinity and can mobilize, that's one of the best times to move in. If the whole enemy team is there, you have a teamfight with the enemy team weakened by the dragon fight (lategame, it's not a huge advantage, but it's something). If less than the whole team is there, then they're at even more of a disadvantage. Either way, you should come out ahead, and (depending on the exact situation and outcome) might even be able to pull a Baron Kill out of it.