I've been using the free tier for two years and am yet to run into anything shady. Saved me countless bucks in the meantime (before arguing that it's like two seconds of work for you, remember that other countries do exist, and even something like DigitalOcean is pretty costly for many of us). Unlike many other free tiers you are not able to create any paid resources unless you opt in into the paid tier.
Oracle is not the kind of company you want to test with things like that.
Trust me, I've worked with Oracle. They'll assign sales assistants and lawyers to you. They'll chase you down for pennies. Doesn't matter if you actually owe the money, they'll get it.
They spent fourteen months chasing up me and my project manager for $220 that we didn't owe them. They just decided that we should pay it and they'll work out if we actually owe them anything afterwards. The credit card had expired years ago and we hadn't used their products at all since 2016. Doesn't matter, they still spent a year assigning more and more of their team.
Eventually we just paid because it was cheaper than letting them take our company to court. The time taken from me, my line manager, and the project manager answering calls/emails/letters probably added up to a lot lot more than $220.