From what I gathered from the links below, they were intended to stop mining if an unintentional hard fork would have happened. Or maybe also to force miners to upgrade? Did the Frontier release not yet have the ice age mechanism?

The wiki page suggests that there was an option to ignore the canary contracts. So you could mine nevertheless without recompiling the source.

There's no such option with IOTA as the coordinator is closed source.

https://github.com/ethereum/wiki/wiki/Bad-Chain-Canary

https://blog.ethereum.org/2015/07/22/frontier-is-coming-what...