Our sites were showing popups so we're deleting Sweet Captcha plugin.
Sweet Captcha is reported to be distributing intrusive adware and even malware (generating site virus warning reports):
https://blog.sucuri.net/2015/06/sweetcaptcha-service-used-to-distribute-adware.html
WordPress should include a remote security mechanism on all sites, to disable plugins that become malware or generate big security risks.
