Quick story, but before I start, full disclosure: This story is not my own, but from a good friend of mine. He gave me permission to post this. This is told from his perspective. Some details were changed to keep things anon.
So awhile back I set up a mail server for a new client I'd never dealt with before. It was a pretty simple and relatively small setup, 20 or so users. I sent them an invoice but instead of payment I got a reply back saying the boss had gone overseas and because of that they weren't able to fulfill the payment. They refused to give me any more information so being the patient, kind man that I am I gave them a little more time. I kept pestering them for payment and each time it was the same or a similar excuse, boss is still overseas on a business trip, he'll be back "soon".
Yeah right.
2 months later I get a response back from them saying oh hey the boss is back! Buuuuuuuuuuuut he's gone overseas again but don't it won't be a long trip!
.....
Long story short, after 6 months of banter and excuses I VNC'd into their mail server, simply disabled it and waited for the impending shitstorm.
The very next day I get a panicked call from the client as the very fabric that held their company together had crumbled! The precious mail server that they needed so badly was down oh no i wonder how that happened? ( ͡° ͜ʖ ͡°)
The call went a bit like this ($NC = New Client, $F = My friend)
NC: "We've just had an emergency, our mail server just went down! Everything is on there you have to do something!" F: "Hmm that's intersti-" NC: "You must understand this is absolutely mission critical we NEED our mail working!" F: heh "Well, see, the problem is you don't own a mail server." NC: "wat." ME: "Well you kinda never paid for it, so unfortunately it's stopped working and there's absolutely nothing I can do..." NC: "muffled voices Alright, fine!" F: "So I can assume I'll have payment ver...?" Line goes dead Next day I receive the payment in full and would you look at that the server magically started working again! Haven't heard back from them since.
TL;DR: VNC access is super effective when money is being withheld :P