If one day, ADA is used as a form of exchange medium, how can we make sure that both the buyer & the seller are getting what they promised? For example, if I purchased a computer from a seller with ADA, but the seller turned out to be a scammer. How can I cancel my ADA transaction? I think currently there is no way to cancel such transactions. Maybe there should be a sidechain for pending ADA transaction in place to secure safe purchase of merchandise. These pending ADA are validated before been sent. So both parties are satisfied.
I believe forms of smart contracts could probably be applicable to scenarios like that. It would not surprise me if at some point there are boilerplate contracts for relatively simple transactions like that one could use.
Someone who is more well versed in smart contract deployment would be a better person to answer though.
Your signature to the delivery company could act as an automatic trigger for ada redemption at the seller side ? Is that what they call an Oracle ?