Just something that jumped into my head last week, and I keep thinking about it so in the interest of laying it to rest...here is my very non-scientific observation:
It seems to me, based on the 4 A3000s I have owned, that Amigas that are used regularly and have not sat for a long time unused are less likely to have leaky original batteries. I recently aquired two 3000s that sat for a period of time, one the 3000UX and another a 3000 I picked up from a gentleman here in Atlanta...both have leaky batteries (the UX has its battery removed already, the 3000's will get replaced this weekend along with making the int2 mod). But the other two 3000s I have owned were both used regularly throughout their lives, and both had original, non-leaking batteries. I still have one of them and it's still not leaking.
So what I was wondering is...is it just coincidence, or do they tend to leak more when left sitting for a long time? That's all. :-)