I would negotiate on that non-compete as well. It sounds like its a blanket agreement where you can't work at all for three years in a 50 miles radius. Not cool and slightly unfair.
On the other side of the coin, I have assistants that work with me on a regular basis sign a 2 year non-compete agreement. But it's not a blanket agreement which would make it difficult for them to make a living.
They could work competing directly against me with whatever clients they find on their own, even if its next door to my studio. But they can not work for any of my clients for 2 years after they stop working for me. I'm not going to spend the time training my assistants, then have them put up a shingle of their own, and then steal my clients that I have worked hard for, and ones they now have inside knowledge about.
Having them on the inside in your business is a distinct advantage to them if they were going to compete against you. They would understand your deliverables, policies, pricing strategies, negotiation terms, how you sell your clients, and so on. If you knew all this about your competition, wouldn't that a great advantage for your position? It's bad enough that they have all that inside information when I am directly competing against them on an estimate for new clients, but having them use that information to steal my existing clients would really suck.
Without a non-compete agreement, if I did hire an assistant or second photographer on occasion, it will be strictly to pack and unpack gear, run for coffee, and other menial tasks. I wouldn't be teaching then anything related to photography, techniques, business, contracts, pricing, operations, etc. Since there is no agreement, they could use anything they learn to their advantage.
For my assistants with a signed non-compete agreement, I am willing to give them more info on the business knowing that I won't be competing directly against them with my client for at least 2 years. After than, its fair game and business as usual. And on new clients, they would have the upper advantage since they know how I operate, but I wouldn't know much about their business.
If they don't like the non-compete, and are happy to just get me coffee and carry my equipment for me, then we'd get along just fine 
Non-compete agreements are fair, as long as they are written in a fair manner.