We have received reply from Electrum author. Plugin won't be included in wallet by default. Author believes it would create a law risk to add mixer into wallet. Our hook was merged so our plugin will work with new version, but it will need to be installed separately.
We have published an article at r/Bitcoin about how to use ChipMixer to avoid upcoming "declare cryptocurrencies" US law:
https://www.reddit.com/r/Bitcoin/comments/6jzc41/easy_way_to_avoid_upcoming_us_declare_btc_law/Well, Electrum's reasoning isn't that surprising tbh. They obviously want to be free of any affiliations to bitcoin mixers/tumblers even though they offer more anonymity to transactions which is somehting that bitcoin is based on. After all, they are offering this service and they are free to do whatever they want to. But still, downloading it separately isn't that bad either.
The crypto declaring law in the us is completely absurd. There is in my opinion no way that they can check any of your belongings to see whether you have bitcoin or not, because it's just not possible... There are infinite amount of ways that you can hide your recovery seed/private key, which only you know. But Chipmixer's idea of having a 2-2 multisig is brilliant as well. Some skeptism on reddit i see right now but i think security of my funds aren't really a concern with chipmixer.