MacBook Pro battery replacement and mounting tab reinforcement

Recently I've worked on 4 unibody MacBook Pros, models designated 2009, 2010, and 2012. One of the 2012 models had been dropped on the corner where the battery is inside the case. This broke both of the mounting tabs that hold the battery in place. As part of taping the battery down, I disconnected the battery's cable from the motherboard so that I could get tape on it and move it into the right place without stressing the cable. I then reconnected it. This was essentially what would be done if I replaced the battery myself. My disconnecting and reconnecting the battery did no damage to the computer. But Apple says that users should not replace the battery themselves. However, it appears that doing this is a lot easier, than, for example, replacing the hard drive cable, which I had to do on another of the MacBook Pros.

1. Is it safe for a user to replace a MacBook Pro battery, assuming you use a plastic tool to remove the cable from the motherboard? Or is doing this one of those things that, done properly, might need (as an example to illustrate the issue), some arcane power device plugged elsewhere into the motherboard while the operation is done, to prevent (again as an overdone example to illustrate the issue) permanent damage to the VRAM, Boot ROM, and every pixel on the screen? This does not appear to be the case, based on my work on the Mac with the broken battery tabs, but I want to make sure I was not just lucky on that one.

2. Is there a way to reinforce the tabs on the battery? The 2009 MacBook Pro, which has never been dropped, nevertheless has one of the battery's mounting tabs nearly cracked off. Looking at the tabs, they appear too small for the size of the battery.

Thanks.

- Winston