Most acts of sabotage take more than a single action to accomplish, and they likely require tools. I don't require tools for Bad Motivator because of the "notice an existing flaw and just put a little stress on until it fails" idea. Also, Bad Motivator is often pretty subtle - even if the mechanic is the one that triggers the weak point, it appears to be normal system failure rather than sabotage (which is often easy to detect by a trained eye).
I disagree.
Effective sabotage doesn't call attention to itself. For example I could cut the break line on a car, or I could simply loosen a radiator hose. Either way my victim won't get there anytime soon. The radiator excuse also isn't likely to kill anyone which won't draw undue attention. Loosening a radiator hose only requires a screwdriver that a creative PC could improvise in a snap (or just have in his pocket).
The more complicated the system the easier it is to sabotage. Computers can be easily sabotaged just by unplugging a cable. You'd be suppressed at how long it can take some of my colleagues to realize that the Ethernet cable was stolen. Unplug a wireless access point and you can shut down connectivity for everyone. No tools required.
If you don't work in a technical field you might not realize how simple it is for even a moderately cunning person to wreck mayhem. Technical systems are usually designed to be accessible so that they can be easily fixed or modified. This saves time and money, but makes the systems vulnerable to anyone with the know-how and malicious intent.
Clever PCs should be able to shut a system down with a Mechanics/Computers check easily if they don't care how long the system is out. Bad Motivator costs XP above and beyond the normal skill points. You are being mean to a PC who purchased it when you nerf it with all these restrictions.
To allay your fears. Military tech is designed in most cases to resist sabotage, utilizing redundant systems and trained personnel. There is a reason beyond corruption and graft that it costs so much more. Unplugging a single switch in a casino isn't likely to shut down the security system as there are probably backup systems. If you could get the backup too then it's a different story. More obvious though.
Businesses are likely to have critical systems protected in some manner, but everyday systems? Not so much. How often do you look under the hood of your car to see if there are any new parts?
Active sabotage shouldn't require talents. When it comes to Bad Motivator it's perfectly acceptable for the GM to say, "No, that won't work. They scrupulously maintain this system." A PC should understand that.
Edited by Aservan