When is a person technically hired?

Can I get switched for a person even after i get hired?

• So Five Guys burgers and fries is opening the 16th here. They had a posting on craigslist saying that they will be hiring people on the spot outside of where it is being built. So I was one of the first ones there and a filled out an application, got interviewed, and got accepted (They said I am hired with a handshake). They said they will call me next week and tell me when orientation is. Well apparently 230 more people showed up over the course of the day. So I am wondering, even after saying I got hired and stuff, can they switch me out for somebody else out of those 230 people that could have qualified more than me? or is it final and I will be getting a call next week? I even got a little sheet of paper saying stuff like "You will need slip resistant shoes, which you can get at walmart" which means I already have to buy shoes and they cant say no because if i buy them and not get hired I can ask them why they made me buy them if I didn't even get the job. They may seem like a answered question already, but i am just very impatient and am worrying that they could just choose someone else over me. Please serious answers. Thanks

• Answer:

  You should be fine. Even if they don't hire you, it's not like you are losing out on a million dollar a year job.