Crytocurrencys are really dangerous, as noone really has an identity. You have to know who you're trading/lending/doing business with. He could just run away with all your time and efforts if you make a mistake. Always escrow, always ask for collateral.
even with a trusted member? (if in this forum)
there is always the chance that a trusted member, become crazy and scam you
because he have economic problem in real life(talking about serious problem, imminent lose of your house ecc...in a situation like this everyone could become a thief)
because one of his family died recently, and he want revenge in any form, or because he is sad and don't care anymore about anything
you can go on, basically any real life problem could affect any users in a bad way
but besides this , usually high trust member are trusted you can deal with them without worry about