Yeah but I wouldn’t recommend that to just anyone. Copper braid can easily become solder soaked and then become a rigid connection instead of a flexible one. Only use copper braid if you can guarantee that nothing soaks.
I’d rather the current flow through the conductors I purposely soldered instead of intermittently conducting through the touching nickel as the board flexes and vibrates.
The contact doesn’t matter at all, because the electric potential has already been equalized over the top conductors. The sides touching would even be beneficial, as the overall resistance decreases.
I don’t know the actual reasons why it’s recommended not to weld in the center of the bottom of the can. Some engineer somewhere knows but every person in the industry I’ve spoken to just says not to do it.
There’s no way that us welding there can help the cathode tab weld on the inside of the can though (at that spot) and since there could possibly be a negative effect if we welded there it seems to be decent advice from the manufacturers.