if anything all the hair blowing them around will make them form knots kind of like the wind. i dont know if the heat would change anything, but i did when mine were new for a few times and it was fine.
I heard someone say they bought one of those hair salon blow driers at a garage sale and they are lovin it! Seems like if you were able to find one of those or something similar it would be great for people with baby dreads also. Of course if they are locked up pretty tight any ol hair dryer would be fine.