This is false.
When you respawn, hence, die, your player object that has the unique ID assigned to it ceases to exist and the new player object has a new unique ID assigned. It's the same as the id of the %client object you get by findclientbyname(<Name>). When the player leaves, the connection object ceases to exist and when they rejoin they have a new ID assigned to them.
Now the catch here is, you can use a function after the "player" in a line should you want to do something directly to your player.
It does basically what Get ID does if you use it how I typed, however you can use it to directly affect a client's player object like so:
findclientbyname([name]).player.setplayerscale("5 5 5");
This will set the targeted player's scale every time, so long as they have a player object (they aren't dead)