Filmmaking sure is a tough old business - even if you've got all the money, time, and personnel you could ever want at your disposal, there's no guarantee everything's going to work out as planned.
And then there are times that, whether you're a big budget production or a tiny one, it's simply less hassle to seek forgiveness rather than permission.
Rather than have a dozen boring bureaucratic conversations with producers, location managers, and city officials, why not just cut through the red tape by shooting your desired scene "guerrilla style" without proper authorisation?
It's incredibly risky, of course: you can get caught and turfed off the location, you can get fined, and you might even risk voiding the insurance for the film's entire shoot.
In our highly litigious, health-and-safety-conscious present, most movies with decent budgets won't bother taking the risk to "steal shots" unless they can guarantee the cast and crew won't face damaging repercussions.
But these 10 films - most of them unsurprisingly from decades past - decided to take the chance and just... start shooting regardless of what local laws and producers said they could do.
Thankfully in each case nobody was harmed, and in many instances it even added tremendous bustling authenticity to the scene...
10. Nicolas Cage & Elisabeth Shue - Leaving Las Vegas
Mike Figgis made the uncommon decision to shoot his eventually Oscar-winning 1995 drama Leaving Las Vegas on 16mm film, which as opposed to the bulky 35mm cameras typically used by Hollywood movies allowed Figgis to shoot his film under a fair veil of anonymity.
The smaller 16mm camera allowed him to stage scenes on the streets of Las Vegas despite the fact the production didn't have the resources to shut down the Strip for filming.
As such, many of the scenes that show stars Nicolas Cage and Elisabeth Shue talking out in the streets of Vegas were simply filmed while the hustle and bustle of the real-life Strip was going on around them. No permits, no shutdowns, no nothing - anyone could've interrupted a take at any time.
Though the small crew mostly managed to blend into the busy Vegas environment, this did reportedly result in Figgis shooting a number of scenes in just one take to avoid attracting the police's attention.
Figgis was ultimately pleased with how it turned out, resulting in a more authentic, almost documentary-like feel to Cage and Shue's performances.
And you'd never guess so many of the scenes were "stolen" without permission from the local authorities, because they have all the gritty polish you'd expect from any Oscar-winning movie.