Budvar,
"...usually drive home knowing we are absolutely ******ed...does that make us all irresponsible?"
The answer is, quite simply, Yes!
I'm afraid that if you wipe someone out on the M3 in the early hours on the way home the fact that you couldn't afford to buy a house near LGW or LHR would be no defence. Even weaker would be the admission that, because you are longhaul and don't go to work that often, you decided to live in Somerset as the lifestyle is better.
The beak would simply ask why, if you were absolutely *****ed when you landed, you didn't crash out in one of the many airport hotels. Again, "I couldn't afford it Your Honour" would be no defence.