MickyDee :
I use small zip lock bags for each spare battery that way nothing touches the contacts and they are water tight.
I got you there, that's how I do it too when storing my batteries.
As for Duck tape remember it will leave a residue on the surface of the contacts that will affect conductivity
I'm quite certain he meant while battery is in use, so if the battery terminals is already in contact with the camera, then how it it posible to get adhesive residue on the contacts/terminals?
Anyway It's my silly quick fix but if he really want to fix it then either get a new cover or cut exact same size of thin hard plastic like the cover then place it over where it suppose to go the cover it with thin foil. Now use a glu gun to melt glue over the foil until it's all covers, let it cool down and remove the hard plactic and foil.