I have a web page, say http://domain/purchase and in this page, I have a web form. User, on submitting this form (which has validation, both client-side and server side and won't be validated until fields are filled appropriately), would be redirected to another page, where (s)he can choose other things, and specify other settings and then purchase our product. Say the second page is http://domain/options.

So, user comes to our site and visits http://domain/purchase, fills the form, submits it, and then would be redirected to the second page, http://doamin/options?parameter1=value1&parameter2=value2, which contains parameters from the first page. This is very common in passing parameters between web pages (or technically, between URLs).

Now I was reviewing my website, and saw that Google had indexed some of my redirected web pages and URLs, like:

1. http://domain/options?parameter1=value1&parameter2=value2
2. http://domain/options?parameter1=value3&parameter2=value4
3. http://domain/options?parameter1=value5&parameter2=value6
4. http://domain/options?parameter1=value7&parameter2=value8
5. http://domain/options?parameter1=value9&parameter2=value10

This means that Google Bot has visited our http://domain/purchase page, and has filled our form, and has submitted it, and was being redirected to the other URL, with corresponding parameters. This is the only way that makes sense to me. Does Google really fills forms?

PS: All parameters are meaningful, meaning that they are not filled arbitrarily. For example, the phone parameter in indexed pages has correct phone numbers. How is it possible?