SEC ICO REGulation is just release, and all the tokens will be securities, better to kiss good bye and stop all your ICO scams 
https://www.sec.gov/news/press-release/2017-131
https://www.investor.gov/additional-resources/news-alerts/alerts-bulletins/investor-bulletin-initial-coin-offerings
https://www.sec.gov/litigation/investreport/34-81207.pdf
https://www.sec.gov/news/press-release/2017-131
https://www.investor.gov/additional-resources/news-alerts/alerts-bulletins/investor-bulletin-initial-coin-offerings
https://www.sec.gov/litigation/investreport/34-81207.pdf
This is already completely irrelevant at this point as many ICOs are only available for non-US residentials. To be able to participate in the ICO, you should agree to their terms which includes you being a 'non-US citizen' and only then will you be able to coins. Not sure how it would go if US residents try using VPN services to buy from ICOs but it would still be a big risk if they do so.