The internet can be a downright nasty place with scammers and spammers in abundance.
When a site opens up to user generated content it better be prepared to deal with spam. Fortunately Ucommerce supports multiple kinds of protection.
You can enable customers to report abuse and thus bring any unsuitable content to your attention for approval. Abuse can be reported for both reviews and individual commets.
By default content reported as spam is still displayed on the site to prevent users from removing content from the site until it can be reviewed and approved. If content is to be removed from the site immediately you can do so as well by modifying the filters for user generated content which is not to be displayed.