This could in theory happen, but in my examples I'm adding the url right after someone converted -- paid for a subscription or completed an order. Those are unlikely to be shared with someone else (ideally). It's arguably more likely that the user will share it with themselves on another device, in which case the overall approach will work well.
I should also point out that the url tracker isn't meant to be persisted across page views. It's only done once at the moment that the user identifies themselves to your service.
I should also point out that the url tracker isn't meant to be persisted across page views. It's only done once at the moment that the user identifies themselves to your service.