It's the one built into vBulletin, yes.
I probably don't get any bots because I have "Under attack mode" in Cloudflare turned on at all times, something that's mandatory for a gaming community due to DDoS attacks. This mode requires JavaScript which probably stops pretty much all non-human visitors.
I don't mind to give it a shot though by disabling reCAPTCHA.
It will give you a full report of anything it does catch. No need to mess with your CF settings but yeah, lose the reCaptcha at least.
Not sure, as I don't use that, and it obviously has its own deal and bypasses vBulletin stuff.
Well, tapatalk defaults to in-app registration. Last I checked, leaving in-app reg enabled on the plugin would divert away from all forum registration security measures configured on vB (i.e., CAPTCHA, random questions, anti-spam plugin interventions, etc). The tapatalk in-app reg process only required that a user enter an email address and a password to complete registration. I'm unsure whether or not tapatalk has fixed the issue.
If you're at all interested concerning the above described behavior, here's a thread in which forum owners were trying to get tapatalk developers to address the issue or at least come up with a workaround for vB 3.x/4.x as applicable to various devices: https://support.tapatalk.com/threads...rations.20426/