A way to protect yourself from outbound links?

[blaketar]

Intermixed in our site is an events section which allows people to post craft events along with a link to their website about more information.

While most coordinators are legit every now and then an entry will contain a link to a site not at all related to our niche and obviously posted as a means to obtain a link.

Google (and other engines) outline an importance on "Not linking to bad neighbors" and in most cases we simply delete the event or link but sometimes web site owners change, domain information changes, etc.

Can we protect ourselves from outbound links by adding the nofollow tag, are their any other alternatives other than "no links, period"?