This has happened to me too, especially as support roles that usually don't get in the cap zone, but flank it to get a better vantage. Once it happened that the enemy took both areas at once and I had no chance of getting back to my front line.
You might argue that I deserved to die for not defending my objective, but how about this:
If I'm moving out of the taken objective don't kill me--don't have a timer, just if I'm moving in the right direction (retreating back to my defense objective), don't kill me. If I'm just camping behind enemy lines, fine, teleport me back to my spawn. But don't kill me. I'm too young to die.