Iphone battery is already pretty close to replaceable by this law. You need a common tool to get in (trident screwdriver is available in most DIY shops), then glue tabs can be pried by hand. Doable for layman? Well, some people are afraid of opening up a device in any way. How do we (or, rather, lawyers) draw a line?
I know the glue is unnecessary because every time I've replaced a battery, I didn't glue the new one back in, and my phone performed fine.