So I've been wondering if there will be any issues that may arise with cross-save if two completely unrelated people happen to have the same exact gamertag on different platforms. I play on PS4 and a buddy of mine apparently shares an identical gamertag to someone else on Xbox. We know this because of the times we have looked up my buddy's stats via Destiny Tracker. When cross-save becomes a reality, is a situation like this going to cause any issues for these players? I don't quite personally understand how the game itself shares the data with the different platforms, so I am not quite sure how it will play out with this, or if it will have any impact at all. Hoping for some clarification because I obviously don't want my buddy to somehow lose his character/account data when Shadowkeep drops.
For cross save, the accounts in question are going to need to be linked to your bungie.net profile so regardless of what the "name" is it only the account that is linked to your bnet will have your save.
Your characters are bound to your bungie account. You can have the same name as someone else on battlenet and still have separate characters. You will be setting one platform's account as the primary one and then linking your other systems to that account I believe. So on each system you will have a different name, because it is using that system's API for multiplayer.