They're in for a very pleasant surprise.
I'm very aware of how most stage bloods are a real pain in the arse to clean up. I try very hard to know exactly what to prepare for when I walk onto a set. I want to know what kind of textured walls (and ceilings) I'm dealing with, if there is upholstered furniture I should know about, and what kind of flooring is underfoot. If I have all this information beforehand, I can mix up some formulas for blood that is least likely to pose any staining problems.
Of course, I'm not always granted this luxury so I do have to make it clear to directors that there may be a paint job in their future due to blood stains. But as far as I know, no one has had to do that yet.
I'm also always armed with enough plastic sheeting to suffocate the entire crew six times over and a myriad of cleaning supplies. As soon as the director yells "Cut!" on a freshly blood-spattered set and then nods to me to re-set, the next thing you hear is my voice yelling "All hands on deck!" to put the clean-up crew into action. I often joke that my team could pass a Luminol inspection.
You see, I was taught at an early age that if you're going to make a mess, you should always leave the area cleaner than it was when you found it. Those childhood lessons have really served me in my work with bloody FX.... especially since I'm the one that nervous home-owners are keeping a very close eye on!
Now, I'd like to take a moment to address something strange that has happened to me a few times while I was on a set. I can usually predict that it will happen when I'm cleaning up my own mess and someone comes up to me and exclaims 'Oh, you have garbage bags!"
Yes, dear readers, I'm about to tell you that there has been a time or two where I was the only one on the whole crew that brought cleaning supplies. What I'm almost embarrassed to admit is how many times I've wandered around a location picking up the debris from other cast and crew members... and how many times the home-owner has thanked me and expressed wishes that I'd been around for previous shoots at that location.
There's really no excuse for that. Whenever I hear about crew people leaving a real mess for the property owners who were nice enough to let them shoot there in the first place, it bothers me a lot. It makes the whole production look ungrateful and unprofessional, and it also gets people to think twice before they support independent film again.