Well guys, I don’t bother with adding any extra codes to anywhere.
I just simply find the lines in the theme codes which are pertinent to the date and author and I just remove them.
I’ve been doing this for a long time with many of many themes, works every time.
The only downside is that when the theme is updated sometimes you have to do it again – or just upload your edited code. (depends on the theme/update).
But since I am paranoid I keep many dated backups (even as plain files!) on my local machines anyway, so it’s not a problem.