Perhaps the rules are intended to encourage looting, just as they are intended to make it hard for PCs to die. Sure, you can fight the rules, but that doesn't mean that you should.
My complaint with that is it sounds like it would make it harder for the GM to actively push a couple of the themes of the game: if you're living on the fringe of society, you should be (1) scrambling for money and never complacent about it; and (2) you should be hungry.
Okay. Players are hungry for credits and scrambling for money. Just like heroin junkies. Why does it break the spirit of your campaign that players, when put in that situation with that same level of motivation, behave in the same way that junkies behave (stealing everything that's not bolted down and selling it to fences for pennies)?
The more you punish players for adapting to the lack of money by trying to take things that have value, the greater a problem you're creating.
GIVE THEM AN ALTERNATIVE REVENUE STREAM AND THEY WON'T CARE ABOUT LOOT! (in 99% of cases)
People are smart, give your players credit for being intelligent enough to step over the pennies to avoid pissing off the guy who's giving them the hundreds.
If it's still an issue, TALK to them like they're adults and explain that whatever looting they do that doesn't directly help them with their missions (i.e. stealing a Lambda to impersonate Imperials) breaks what you consider to be the spirit of the game. If they still refuse to listen to you, then they're being assholes and should be treated as such.