The network nodes only accept the first version of a transaction they receive to incorporate into the block they're trying to generate. When you broadcast a transaction, if someone else broadcasts a double-spend at the same time, it's a race to propagate to the most nodes first. If one has a slight head start, it'll geometrically spread through the network faster and get most of the nodes.
The double spending exploit would be done by the same person. There's been an update to Bitcoin called replace-by-fee which means you can replace an earlier, unconfirmed transaction with one that has a higher fee. https://bitcoincore.org/en/faq/optin_rbf/
In other words bribe to double spend.
I love when you use regular person language to explain things to your Minnows @dan lol
why was this comment flagged?
Because next gen crypto is on a flagging rampage
what, seriously - thanks for that info - never knew bout it