How do I null a theme & will Google penalize me?

I have a theme I bought, so I have the license. However, I want to install it on more than one niche site. Since I don't think I could do so with just one license, how can I null it? If I do get it nulled, will Google somehow penalize me by seeing in the PHP that the license authentication was somehow stepped around? I have lots of websites I want to use the same theme for, so I would like to avoid paying every time I wanted to install it, if possible.