>arguably, overwriting snapshot'd versions is a good way to break peoples applications, so it's not necessarily good.

It is true that it can break other applications, however, if someone is using a snapshot dependency they must realise all the risks. This is how it's done in Maven.

>However, if you request a tag 1.0.0-SNAPSHOT, bower doesn't care about other tags, it will fetch this specific one. Overwriting this one specific tag is all that should be necessary to meet this use case

How would you overwrite a tag? You have to delete it first and then push a tag with the same name. However, ```bower update``` will get new code, as it will assume it still has the old version, because the tag name has not changed. Thus, we have add some unique suffix after the plus character.