A standard Joye 510 atty will want to pull about 1700mA. A LR at 1.5Ω will want to pull about 2400mA. That little tact switch that is used is rated for about 50mA. So with a LR atty the switch is expected to handle 48 times the current it's rated for. These types of switches are also not very robust, they are not made for the constant activation that we subject them too.
Trying to cram the components into a 2AA box is part of the problem. There is no room for a decent switch, the switch is right next to the leakage point and refilling means carefully navigating the wiring. Leakage into the box is a design flaw the wooden bottom feeders out there don't have.
HighPing's mod addresses two of these issues. He moved the switch away from the
juice bottle, placing it under the battery, and sealed the tube/needle atty connection.