Ask HN: Non-compete in freelancing contract?

A potential customer offered a freelancing contract which would prevent me from working with any of their customers until 2 years after working for them.

I'm not 100% sure whether or not this is acceptable to me. I don't intend to get their clients but in reality this sometimes happens as I become part of their network.

What's your experience and opinion on this kind of arrangements?

Thanks for any advice!