I was permitted to close my account....without any hassle. Sign into my.roku.com and delete account is as the bottom. Selecting "don't want to use this anymore" gives you a box with 255 charachter limit (because of course they don't want to hear a real reason) and then when you hit send you just get "Thank you, account closed, if you come back you will need a new account"
Surprisingly, suspiciously, painless.