Google reCaptcha is en excellent way to protect your site from spam generated by automated bots. In particular, reCaptcha prevents bots from filling in certain forms and creating accounts. wp2print has built-in support for Enterprise reCaptcha which protects the following pages:
This is an example of the Login and Registration forms protected by Enterprise reCaptcha:
To enable reCaptcha, visit the reCaptcha tab in the wp2print Settings, then enable the checkbox as shown below:
The parameter Quality threshold allows you to adjust the sensitivity of the test. Lower values will allow more spam registrations but will reject fewer real users (false positives). Higher values will prevent more spam registrations but will reject more real users (false positives).