I'm on my way to Stansted airport and I realized I forgot to print my boarding pass and I also can't use the mobile BP as I'm a non-EU citizen. Would Ryanair actually charge me 15 pounds to get the BP?
Completely depends on the agent.
When I was in London in January, I failed to find anywhere to print it, and when I got to Stansted, one agent did want to charge me 15 quid. Discretely went to another agent, who printed it for free.
Don't know if being EEA or non-EEA matters, but it could (with EEA pax being treated more strictly, seeing as non-EEA pax have to visit the counter anyway).
No, Ryanair no longer seems to charge this silly fee. I was in a long line of people who likewise forgot to do it at home and nobody was charged for the service. However I did see Ryanair charging 50 pounds to people who forgot to check-in online, so they probably do enforce some of their rules.
Yes, you may be charged. I was charged at Wroclaw airport when I manged to lose my printout between leaving the hotel and the airport. Based on others' experiences, it appears some agents may waive the fee, but you cannot rely on this happening.