Having to have an extra $200 around to leave as a deposit at the library would exclude many many library patrons, and is definitely not the "best system". It's one of the worst possible systems.
Where I live, you need a similar deposit just to get electricity in your place, if you don't have credit.
A patron is generally someone who pays.
Nobody is paying in this situation; there is a deposit which is refundable, with reasonable interest competitive with bank savings accounts in the area.
Where I live, the (one and only) power company charges deposits against new accounts with no credit or bad credit:
Why would a library not charge deposits for borrowing? Because people need to be able to take books home (as opposed to reading in the library) more than they need electricity?
Because public libraries are public services and are not a for-profit industry. Their priorities are in serving the public, rather than generating income.
An alternative question could be: Why doesn't BC make electricity as available to their poorest citizens as NY makes books available to theirs?
