aggregateRating and review under /Person

Hi,
I'm building webpage and a stumble upon a problem.
I have three types of pages (artist, event and venue). The last two (/Event
and /Place) have "aggregateRating" and "review" properties, but artist (i
will use /Person) doesn't.

So what are my options? Googles Structured Data Testing
Tool<http://www.google.com/webmasters/tools/richsnippets>returns a
Warning. Can I do this or is this bad for my SEO?

thx


-- matija urh