hey i too get that problem when i try to make it differently.

Instead of using the snap to object , i advice u to use the `make live ` that we find under modify.

Slelect u r character and use that option. Now make curves on that as it follows ur hair. Use the onption in rendering menu set Paint Effects->Attatch brush to curves. u can get u r hair and move it with the face or head.Hope i am clear in my explanation.

OR the best thing i suggest is use the hair in maya unlimited.Create a shape that resembles the scalp. Assign hair to it and parent it to the head