20 minutes of test are really not enough. I didn't find a significant
increase in spam: if I see correctly, some more inactive accounts were
created and 2 userpages, which had not been previously created, were
added by two IPs.
Let's collect information on
https://www.mediawiki.org/wiki/Extension:ConfirmEdit/FancyCaptcha_experimen…
We can tweak the abusefilters and repeat the experiment another time.
Nemo