[Jabanga]

Miners can't change the issuance schedule. They can only delete blocks and form new ones with valid* transactions, and only if they collude, and are okay with destroying the value of their capital assets.

* transactions where the private key associated with a public key holding value authorizes an outgoing transfer of value.

[CJefferson]

They can stop you spending the money, and the "they wouldn't do it as they would kill the goose" applies to banks and governments too.

[Jabanga]

Yes they can do that. But that's not what the parent comment asserts. With respect to Banks and governments, they're different in that they have a monopoly over their jurisdiction.

[icebraining]

How can they do that?

[CJefferson]

I would recommend going and reading about how the blockchain would in depth, it is complex but interesting.

In short, miners build up a log of all exchanges of currency. While you have to "sign" any payments you make so no-one can steal your money, miners can choose to ignore your payments, and not add them to the blockchain.

Now, if the mining power was spread among many people, someone would put your payments on the chain. However, we are currently in a situation where a very small number of groups (between 4 and 6, depending on when you check), control over 50% of all mining. If they went rogue they could, in principle, lock the account of anyone they like, stopping them spending any of their bitcoins.