Do the investigators need a car to pick you up in a desolate spot in the woods? A player can make this happen by a) supplying a credible retroactive explanation of how she arranged it, and b) scoring a Preparedness success.
A point of some contention in the Trail of Cthulhu games I’ve run is the preparedness skill.
I have to admit, after reading this explanation by Robin D Laws, GUMSHOE system creator, I may have been being a bit to harsh. It does seem to be “Summon Retroactive Deus Ex Machina,” at least to some degree.
This is one of the issues that I personally have when running a game of Trail of Cthulhu. The system is closer to collaborative storytelling than I can really pull off given my personality and my preference for adversarial games. I don’t consider that reflecting badly on the system itself, more on my own inability to stop antagonizing my players with deathtraps and sanity blasting monsters.