The Bhikkhu I meet with, he claims to know living arahants. I am choosing to believe this, it inspires faith.
I personally know lay people who claim to be "enlightened", not through Buddhism but through New Age spiritual paths or cult activities. I feel really uncomfortable when they talk about this, I want to whistle a little tune while I wait for the space aliens to land... Seriously, how does one respond to that? I think this is why Daniel Ingram is so controversial. Maybe he is, maybe he isn't, but it amounts to an unverifiable and grandiose claim.
With that, I defer to the many many posts/threads that already exist about the topic.
"As I am, so are others;
as others are, so am I."
Having thus identified self and others,
harm no one nor have them harmed.
Sutta Nipāta 3.710