If someone were to vote for me everyday in september and if i got my upgrade, you would get a beacon. I Give you the beacon when i get the upgrade. Simple.
Provide proof that you own it, Say that it's there's if they buy your upgrade/ vote for your upgrade then once the deal is over with on there part give them the beacon. You can't be to trust worthy with people online. :P ( Giving a High Priced Item for a Upgrade is a Both sides a Risk.
2 Problems. What if Someone votes every day for you, But someone else states that they "Voted" For you. Or, What if a Person named "Endery" Votes for you sept 1st and a person named "Jacob" Votes for you sept 2nd and Different people vote every day for you. Who would get the beacon?
Whoever say "I Will" Then i reply saying i agree they will, so when i say SURE to the dude who made the offer, he gets the credit.