Really depends what you call bad, you can easily pk on dial up with no issues (unless the telephone rings) if your disconnecting out or lagging then I wouldnt suggest it.
Other than that you should be all good.
I wouldn't risk it man. A bad connection is too unstable, you just never know when you are going to lag or even worse, completely disconnect.
If you DO decide to PK, I would be smart and wouldn't risk too much. Doing rune fights with nezzy + whip + glory etc. won't be as devestating of a loss as it would be if you were to lose a chaotic or ags, claws, fury, etc. due to a connection problem.