I know of at least one free user who had their account terminated for “inactivity” on a personal basis. I also have read multiple accounts of the Always Free Tier cancelling accounts, even when users are actively using them, for seemingly arbitrary “inactivity” justifications. There are also multiple accounts of them deleting paid user accounts with no warning. My personal anecdotes don't have public stores I can link to, but here's a small collection of people who have had Oracle terminate their accounts for seemingly no reason, or other issues:

• Erik Uden's account
• Oracle Cloud admits users could access other customer data
• Tell HN: Oracle Cloud is shutting down free instances
• Tell HN: Oracle Cloud has Suspended our paid account
• Oracle Suspended My Account
  • HN comments lead to another experience and another experience, lead to someone who tried to pay them only to get no support or help

The basic details of the problem seem to be:

• Some people get terminated for never logging into the Oracle portal (but the server use is high)
• Some people get terminated for having CPU utilization low (I guess means you aren't using them)
• Some people get terminated for trying to pay but having weird payment issues
• Some people get terminated even though they're paying, for no reason

There are just much safer alternatives, and even ones with reasonable free tiers, like AWS, or with abundant free credits, like DigitalOcean.