Eh, it's in line with things like [1] - and substantially cheaper than things like [2]. Well below the cost of the employee's time.
EMF Camp sounds like fun, but it doesn't look like they're targeting the get-your-employer-to-pay market. By and large, corporate training doesn't run over the weekend and expect attendees to bring their own camping and cooking equipment! [3]
However I have to pay out of my own pocket regardless and that's way more fun anyway.