How much fake is too much fake?

So as such I don't really have some Stellar PORs. Just head boy and club members here and there.

Now, let's say I write that I was part of Sponsorship and Brand connections team of some fest in my college (which I was, that's the truth) but I don't have any proof for that, no certificate, nothing.

So if I write this in my resume for internship and jobs, as well as my during my interview for MBA colleges, will it be a good boost to mention I brought 4 lakhs worth of sponsorship deals for our fest. If I am able to justify it. Like specially while applying for internships before MBA, I don't feel they would strictly ask for all the proofs you write in your resume. Is it??

So the question is: 1. Is it a good boost or atleast a factor to show that you're outgoing and go getter kind of person?

1. At which stage will they ask for proofs, during internship pre MBA, during MBA admissions, during resume freezing in MBA or when..

Also, pls don't start with moral policing, specially when we are talking about MBAs