I’m not sure how long the option “do this for all block name conflicts” will be active? What means “all”? Doe’s it mean, the popup will not popup again for:
(a) for all blocks of the current copy&paste
(b) for copy&paste events of the current Rhino session
(c) for any copy&paste from now over all next Rhino sessions
It will last only “one paste”. In other words, if you paste only one block instance, the checkbox “Do this for all block name conflicts.” is basically redundant. If you paste multiple blocks at once, it will remember the setting you choose when you check the box for all the block instances you paste.