Meta tags will be indexed if they appear to a page as static html(and if you have search index configured to search for static html in pages). You can hide them with css or html hidden field, but if you try to search for "<meta" the search widget will give you a notification this is a potentially dangerous request and the search query will not complete.
All the best,
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items