Marketo Form Registration Data, but User swears not submitted by them?

[Mark_Knight]

Has anyone ever experienced receiving Marketo form registration fills, then upon contacting them, they swear they haven't submitted the form, and don't work for the submitted company?

We are running a series of Google PPC adverts on search terms, specific to our high-Tech B2B industry, that land on our Marketo LPs. The call to action is to fill in the form to register for a software evaluation 

https://digital.zuken.com/E3_cabling.html#register 

Yet we regularly (according to sales who are following up registrations) encounter contacting people who claim to not have submitted our form, dont work for the stated company and have no idea why we are contacting them.

Has anyone else experienced these issues, or have suggestions on how to overcome?

[Christiane_Rode]

Are your forms set up to monitor for bot/spam submissions -- either through a honeypot field or ReCaptcha? While bots won't account for all suspicious submissions, it's a place to start. 

When you look at the records for the mystery submissions, is there anything in the user record that could indicate malicious activity? If you look at the mystery submissions as a whole, is there anything similar about them? As it looks like you're in the UK, I'm not sure if you're capturing inferred information, but that could also be a place to go digging and see if there are trends there.

Since we're assuming people aren't filling out the form and then forgetting, if you can identify trends with the submissions, it might help lead you to a solution.