The positive side of calling TSA screeners "Officers" is that it dramatically ramps up the negative publicity that TSA has to deal with when one of their TSOs screws up.

Here is one such example, an article about the arrest of Transportation Security Officer (TSO) Minnetta Walker:
The Cypress Times:
TSA OFFICIAL NAILED ON CORRUPTION CHARGES
Published 01/14/2012 - 6:29 a.m. CST

The newspaper would not have labeled Minnetta Walker a "TSA Official" if her job title had been "screener" or "clerk". The tone of the article would have been different as well; had her title been "screener", the author would not have written "Many observers of this case believe her punishment doesn't reflect the seriousness of her crime as a federal enforcement officer."