Not insider :-), only looking for answer to my question:
Who or what prevents me from ring-signing your input and send your money to my address(output).
What this ring signature guarantees. (may I spend all inputs ? is this agreement of this group ? If it guarantees nothing (because anybody can create signature) then why is there (just "smoke screen" for propaganda we are untraceable?))  ... or I'm too stupid.

Edit:
q1: How much money was mined(emitted) and what is total sum of all accounts :-) ?
Edit2:
if you know answer to q1 then you must to know all accounts and their balances.
q2: Do you know how balances change every minute ? [yes] In case, your money are secure, can be blockchain analyzed ? [yes]