OK, if I am say a French Citizen, I can post all I want about the Riots without being arrested while in the UK ? And how will the know who a person posting fro

OK, if I am say a French Citizen, I can post all I want about the Riots without being arrested while in the UK ? And how will the know who a person posting from the UK to a site with the name 'Akhfd' ? Will the media site give up your ID, IP and/or personal information ? Can I call home to the US and tell someone about the riots and ask them to post my info from the US to their site. Will that get me arrested ? Looks unenforceable to me. Maybe all they can do is deport me.