Yesterday I used a VPN (TunnelBear) + ITV (UK) app to watch the Roland Garros final.
For the WC I will download whichever TV channel app that streams the football and use it with a VPN in order avoid geo blocking. I will do this for whichever game I can't watch for free on TV. Given that I live in the EU, and using this as precedent (http://www.bbc.com/news/business-17150054), I don't think this is illegal in any way. Hope that helps.