Taking this as an example - if a strand of hair gets in say in cpu socket of a PC or any other slot of device, what would be the consequences, rather the symptoms if the hair gets in between those pins:
No, not at this voltage. But it could 'open' the circuit and change the impedance of the circuit in the case of a CPU socket. If hair got in between one of the pins and the contacts there could be a problem.
Hair resistance is probably in the MΩ range, I couldn't measure anything with my meter and it goes up to 10 MΩ.
The pins on a processor need to make contact, hair is not going to help that situation and could open the circuit. Use 'dust off' or something to get it out.
A quick google shows that most of the time hair is an insulator, so a hair getting in will make it mechanically hard to plug it and possibly cause an open circt.
First however, define your hair.... Wet/with hair gel/oil/spray/dog/cat/dyed/etc then use google (or alternative) to find the conductivity of it. (Alternatively, experiment yourself)
As others have said, breaking the contact is the biggest issue.
Dry hair is a good insulator, but hair is also great at absorbing moisture...
It can, under certain conditions absorb up to 45% it's weight in moisture. Add a little sweat salts and you have a conductor. As such a stray hair in a high humidity environment could introduce a current path that is detrimental to the functionality of the device.