The IRS was just barely starting a consumer education program before their registration system was shut down pending further legal action.
It's been a while since I obtained mine, but at the very least you have to provide a SSN to obtain a PTIN, and there may be other checks enforced, so it's not quite so bad as implied by "you can get one in 5 minutes". However, unfortunately there is little to prevent PTIN fraud, i.e. using someone else's PTIN.
Someday the IRS will publish a public PTIN database, similar to what CTEC does (see below), which would at least let consumers verify PTIN validity, just as they can do with state-level contractor licenses, for example.
CTEC (California Tax Education Council) at ctec.org is a long-standing example of what the IRS is still trying to accomplish. The other primary example is Oregon, which also licenses tax preparers at the state level. To its credit, CTEC has actually spent some money on public advertising this year to educate consumers on the the need to hire a legal paid tax preparer. (billboards, etc)