maybe you have noticed that immigration getting stricter and stricter. plenty of people getting denied lately in the airports. be prepared for the day when you will be rejected. get a proper visa like everyone else. why beeing a cheap charly???
for the application not. for extension you need ongoing activity. i bet down the line you will have to proof some ongoing activity sometimes. they could start checks on entry. same as they did in the past with ED or volunteer visa… to believe that there will be no check for 5 years is pretty crazy and doubtful