First of all, you did not post enough information. The question is what chip do you use?
For example, Atmel provides easy way of port settings: if you set port pin then it comes input one. So it is not dangerous but only correct way to setup pin as input. For other manufacturers it may [not] be correct. Read datasheet then.
Btw, in subject you have indicated output pin to ground but I do not see GROUND shortcut in message body and example, do you? You just connect one pin with another...
Good days!