For many guitar pedals the DC power lead is centre negative. Which to my personal view is the wrong way round!, we can thank BOSS for this configuration.

q)So whats wrong with having positive on the sleeve of the DC connector.

a)If you are using a daisy chain lead and dont use all the plugs you have 9V hanging about looking for some metal work to short itself out to.

If the centre had been used there is much less possibility of an incident. But thats not what we have so….

q)so how can we make things a bit safer?

a)dustcaps or sleeves,

But where to find such a handy thing. Here……Effectively bolt sleeves.