Could double pitching be harmful?

[Shoemaker]

So it's been about 48 hours and I have yet to see signs of fermentation. I used dry yeast, rehydrated before pitching and aerated really well. I know I know, RDWHAHB...but I figured since I have an extra yeast packet, why not throw it in? Are there potential drawbacks in adding another packet of yeast now?

 

[Rick500]

You probably didn't need to repitch, but it's not really going to hurt anything.