Inactive views

Hello,I have a question about inactive views in a database. Our dbs are only for web client, we have about 30 views, from administration client I can see, that only few of than have built indexes. So I think all the others are not in use. My question is can they affect speed of database or not ? Can we have many inactive views in databases, just in case somebody will need them ?

Subject: inactive views affect performance if their indexes are built…

so if someone uses one of them by accident, it affects performance until the index expires.Performance basics for developers (whitepaper)