Ah, right, travel does take 5 hours. Sabotage production takes 7. Yeah...Well, I don't use those options anyway, so that's why I forgot.
Generally, if you have no unit and high infiltration skill, you can still make it without getting captured into an enemy region, unless the enemy has a really large number camped there. In that case, either wait until your army goes in to cause a distraction (remember, this IS a team-based game) or pick better locations. As people have said before, the infiltrator game, at least after the initial screening, is a very mental game. Skill of the player is very important, and while exact risk cannot be calculated due to seemingly large variations in risk probabilities, skilled players can somewhat mitigate that risk by taking balanced actions in the correct regions.
Basically, find good positions.
