🚀 go-pugleaf

I have a Panasonic model KX-T2355 speakerphone which I really like.  I'm
very impressed with its array of features.  

However, the instructions include installing some AA batteries and they forbid
using alkaline (and I think also nicad) batteries, and insist that I use 
carbon-zinc batteries.  Since everything else I have uses alkaline batteries,
and they last longer, I buy them in quantity and I'd rather use them in this
speakerphone also.

I called Panasonic Customer Service, and was told that alkalines couldn't be 
used because when they were exhausted their leakage would ruin the device.  I
asked if carbon-zinc didn't have a similar problem, and they said no, they 
didn't.

Does anybody know if this restriction makes sense?