Guess I was wrong again =) Just seems like a silly (and poor) way to make a charger. I hate seeing stuff like that in commercial products.
Reminds me of your typical cordless phone, the ones that use NiCads and constantly trickle charge them when they're on the hook, usually last about 1 day off the charger and go bad inside 6 months from memory effect on the Nicads. Finally bought a decent (still inexpensive) Panasonic cordless set they last 2-4 days off the charger and at a year and a half old they still hold a full charge. Better yet the battery pack is a simple frame around 2 AAA NIMHs so when they do finally age down replacing them will take less than a minute.