Artists and private social accounts

I found an artist's Instagram username on a post, but it's not in their artist tag. I looked up the account to verify it exists when I noticed it was set to Private. Is it okay to add it anyway, or would it be better to leave it off?

OK to add.

It would be better to add in case the artist sets his account to be public again and uses it for his artwork.

Okay, I added it. I figured I probably should, but I remembered how we allow some artists to have separate tags for their SFW and NSFW work (according to their wikis) and thought private accounts could potentially fall inro a similar category (like if it was being used for the artist's private life, for example). I guess the artist would have to ask us directly if they really don't want it associated with their art. Thanks.