@olivierlambert I think some kind of registration would be a great idea. I'd also love some kind of way to kick back to you guys for the excellent work you've put into these products that's not a subscription. XCP-NG + XO have let me span my home lab from my basement into a rented office space and into a dedicated box.
I don't generate revenue so a subscription for this would be out of budget, I'd love to kick back something for the work you guys have put in. While not a perfect example, something like Untangle's home license at $50 / $150 per year depending on features would help fill in the gap.
Keeping a registration option to remove the nag in lab environments would still be a nice have