hikki only gives her e-mail address to those close to her.. so i would say family..
I think that it would be extreamly rare for her to give it out to a fan.. so if she does.. she must really trust them not to give it out..

I do admit that i know one such fan.. but he won't even tell me it... and i am very close to him...
though he hardly sends her mail... if he does have questions then he does.. but she's so busy that only one gets answered..

I hope you understood what i said.. and please don't ask me to bother him to find it out.. i did that for a whole year and it got me no where.. so i am not gonna try anymore!