Well I can tell you what could happen, they tell you to disconnect the negative so you don't electricute yourself.
What will happen is the car will not start nor will the electrical lights, radio ect. Unless your doing electrical work on the car don't dissconect the battery
First of all - tHe engine will stop as soon as you disconnect the battery. Secondly - you risk being electrocuted if you do that !
Some alarms systems have a protection function which will prevent starting the engine is somebody tried disconnect the battery and connect it again. Also what might happen is that your alarm system doesn't have memory in the case if you disconnect the battery. Thus, if you do disconnect the battery it will reset the alarm system to the default factory settings. By default, the alarm system will block starting the engine.
If you are careful and do not let the positive cable to the alternator come in contact with the motor or frame, nothing will happen. It is just a lot easier and safer to disconnect the positive cable from the battery. It saves possibly shorting out the cable and possible ruining the battery.
The engine will not run with a failed distributor.
If you disconnect the TPS sensor, there would be hesitation on acceleration.
Disconnect the transfer case!
For some reason when you take a plug wire off while the car is running it blows the control module built into the distributor. You will have to replace the whole distributor to fix. I have had this happen twice on my 96 Cirrus.
bad relay put your key in the door lock and unlock doors if you have a security alarm with horn possibly disabled this could happen.
nothing will happen
no
If the capacitor is charged then the battery will explode.