For major companies, this stuff is easy to find out, thanks to people sharing their experiences as in that Reddit post. There's entire websites dedicated to countless horror stories of Paypal locking out small business funds arbitrarily with no recourse. Google is infamous in never responding to their customers.
If you're going to base your entire income on it, then do a day or two of research. Try and find stories from people who have had serious account issues: stolen identities, suspended accounts, you name it. Call and talk to people at the company and ask them what their policies are.
If you get Amazon on the phone and ask them, they'd tell you their phone support team won't help if your account is suspended. Make them go on record. If they lie, you have a solid legal case to bring forward.
It's okay to take some risk if you have a backup plan. Okay, Google shuts down my business e-mail account. But I have all messages downloaded daily, and I can switch tomorrow to this VPS e-mail server I set up. That's fine.
It's not okay to be so cavalier if an account suspension will cost you your home and require you to lay off two employees.
Again, I'm not trying to rag on the poor guy this happened to. Hindsight is always 20/20. I'm trying to warn people against getting into the same situation he found himself in.