return dummy notification object if notification cannot be shown
np "don't vote" batched

"undo" button don't show the notification more than once every five seconds
"undo" button unvotes every vote you've made on this pageload
batch "np-don't vote" notification/button action

"undo" notification fires at most once every five seconds
"undo" button undoes all votes from this pageload

could use a little polish but whatever