I think it really depends. If you clearly explain that it's highly volatile and a speculative bet, but with immense potential to the upside while 'only' 100% downside, it's fine I guess. Just don't have them bet the farm, but an amount which they won't miss, but are happy when doubled. If someone has hardly any savings, don't. If they have a healthy portfolio or a decent chunk of savings, plus they don't plan on retiring soon, for the love of god let them get a fraction of that in xmr. I think that is actually a crime if you NOT recommend doing so (be it a very tiny percentage). It is their choice in the end. It's all about presenting the full picture (up AND downside, opportunities AND risks), and not hypesell them into pooring shitloads into it.

I've done this, and yes, i get shit sometimes since we're down, more of a joke/making fun really. But I don't feel like I've mislead them or anything (and so don't they). I've clearly laid out how i see things, and not one of them did an amount which I consider too crazy looking at their financial situation. I'm still fairly confident they'll be happy with the advice in the long run. And if not, part of the game. I think the opportunity was good (and could arguably be even better now) so you take a shot. Whatever the result, the opportunity was there. Hindsight 20/20 right?