no one in the history of the internet has ever been arrested for being on a website. EVER. because being on a website isn't a crime.
you would have to actually do something illegal, and let them know you were doing it, before any 'authorities' would think about considering to maybe start the paperwork that might eventually lead to someone, somewhere down the line, beginning an investigation on your internet behavior.
there are c.700,000 users for each internet investigator to monitor and keep track of. guess what? nobody gives a flying fuck about you being on motherless.