I have a "working" Smart Form. It sends in both cases, as it is designed and intended. I run it on two browsers on macOS Mojave and get 2 very different results, beyond that it correctly sends.
1) I fire the form in Chrome: the Captcha screen is displayed, but its content is larger than the form space displayed so that the Captcha instructions above the tiles cannot be read, unless you scroll. And you may not know to scroll.
2) I fire the same form in Firefox: the "I'm not a robot" screen appears, I click in the check box, it sends, Success! But it has NEVER presented the tiles for me to select!!
I have 2 graphics, one for each case... but you don't seem to be supporting the inclusion of graphics. Send me an email and I'll send them to you. My email is in my profile, of course. Many thanks.
I may be mistaken but I dont think you can use captcha or recaptcha with smartforms since you do not have access to the server side. Recaptcha is a two step verification process. First on the client side in which you receive a valid recaptcha response when the box is checkmarked, and then again on the client side when that response is again compared to another response based on the secret key you provided on the client side and the response submitted being both sent to the recaptcha api again.
I guess you could take their word that the client side verification is also being sent, but without knowing you cannot be sure. Maybe the Dev can confirm the two step process is being performed. Without that, one can easily bypass the first verification step...its the second one that is more bullet proof on the client side that has to be performed to work properly to assure the form is submitted from the website assigned to your secret key.
I also when using the smartform with recaptcha experienced a issue where when the challenge tiles came up on my iphone I could select all the right tiles (cars, traffic lights etc) but the submit button was unavailable to click so I was prevented from completing the challenge step. It was way off the screen and I could not even scroll to it. Seems like it needs to be put in a container or something but I did give up on it for that reason.
IMHO, I think you're mistaken. Captcha's are a part of the Smart Form design and implementation. The issue is as you said in your last paragraph, that the display for the Captcha tiles is larger than the space allotted for it so that the viewer must scroll, which is not obvious. Clearly the display space must either be dynamically calculated correctly, which it is not, or it should be full screen, less pretty, but workable.
I suppose one may be able to verify the process is completing and not being bypassed on the server side by checking the history of the Google recaptcha itself.
Hmmn, I dont even see the option for the "secret key" in smart forms any longer. Without that, the second part of verification simply will not work when using the publish website feature. Unless I am missing something obvious.
I guess what really matters is that Bootstrap Studio provides a form delivery service that is simple, easy to use, and provides a security level most people would rather not have to deal with.