Why yes! I did notice that my 3 daughters, age 5, 6, and 10 have pink (and purple) hair. I let them. I bought the dye.... I helped them do it! Why would I do such a thing??
1- It's their hair. Seriously. Not my hair, not my choice.
2- Allowing them to express themselves and my support of it- is good for them
3- Its fun! You only live once!
(as an aside-- I would never have had the confidence to dye my hair a fun color like that as a child- I still don't-- as an adult)
I think it looks pretty awesome, and I am proud of them for finding their own individuality.
We are not exactly a family that conforms to expectations, we set our own and expectations and love it.