Vince,
I agree with your point 100%. I did a lot of research on batteries after NiMH came out and came across information in the energizer.com technical data pages. The reason for not soldering is that the end caps of batteries are installed with plastic spacers that act as one way vents if there is a pressure build up during improper charging. The closed or damaged vents will never cause a problem if the battery never has a catastrophic failure. The main reason you and I don't have problems soldering batteries is that we may have blocked the vents, but no damage was done to the cells themselves. The pack will function properly and have a normal life cycle. BUT IF the pack were to have a massive overcharge or breakdown there is no way for the cell(s) to vent. Nicads will produce oxygen and NiMH's will produce hydrogen that builds up under pressure. Damaged vents leave no place for the gases to escape and an explosion is possible . This is the risk I and any hobbyist takes when soldering a battery pack.

The problem I had was everybody said "don't solder to the batteries" but never said why not. I did some research, and I now know why not. Everyone who makes their own packs needs to know this and decide if saving a few bucks is worth it. I take that risk, but that decision is my responsiblity.