It's because the only valid reasons for not rolling is pure laziness
Uhh, nope. Occasional lack of awareness =/= laziness.

So what you're saying is, you look up the loot list, you find the item you want and what boss it drops from and you want to just do the raid and let ALL the loot timer from all bosses to run out and not give you the loot except for the boss you're aiming for? You want to make everyone else who are aiming for other bosses to wait for your timer to run out? That sounds selfish to me.
You act like everyone who does this does this on purpose. I assure you that's not the case.

And no, I've never had any unwanted loot drop into my inventory in any of the ct/st runs. Cause between running to the next destination with my controller and waiting for the raid to initiate the next fight, I have plenty of time. Move your notification window to somewhere in the middle if it's so hard to see.
I don't wish to do this because sometimes I want to leave a "notification" there on purpose (such as a teleport) and I don't want it obstructing my view in the meantime.