PSP Minis Are Offered Cut Price Ratings According To The ESRB.

Mainly the games have to be rated by the ESRB, and ESRB rating are through the roof! The ESRB have shot down those claims.
[quote]
“The ESRB has a reduced fee of $800 for games that have development costs under $250,000,” said ESRB spokesman Eliot Mizrachi to Kotaku.

"This would likely apply to virtually all PSP Minis.”</blockquote>

Interestingly Fieldrunners' developers' don't quite agree with this sentiment.