getravelop.com question

[2princesses3princes]

We are planning a trip for next year with my mom, who is a city govt employee. I was looking at renting through the getravelop.com site. My question is- what proof of govt employment do they require? Is her city name badge enough? a pay stub? what?
I'd hate to get there and have a problem b/c she didn't bring her proof of employment with us!

Thanks!