GCP definitely has a spending limit. Of course it also (at least in the past) used to take 24 hours to update, so if you had a massive spike in real usage, your site would die for a day while you frantically tried to increase the limit.
Why are people saying this? It's not true. App Engine had a spending limit, but it's deprecated and going away in July. The rest of GCP has never had a spending limit.
The best you can do is build your own service to monitor your bill and manually cut off your billing account if it gets too high. Hope you did it correctly because there's no good way to test it! And the bill notifications can be delayed an arbitrary amount of time with no guarantees, and disabling billing can take an arbitrary amount of time too, so you can still be screwed even if you did it correctly.
I think it's a glaring hole in cloud platforms. I get it, it's hard to implement in a way that is forgiving and doesn't cause a bunch of support tickets from people who set their limits too low and made their site go down. But that's why people use cloud platforms, so they don't have to implement the hard part. It's beyond me why the cloud platforms don't do something better here.
Why should they if they can use obscurity and people's limited comprehension of their complicated systems to produce legitimate, legal bills to customers?
You're talking a 'get paid/don't get paid' decision here.
When you look at this on a high enough distributed level, across enough users, this is the profit margin. Enough people can screw up and then be able to pay the cloud provider, that it is part of the business model. You're required to run some chance of producing a legitimate megabill.
Why be forgiving when your business model requires that you set traps for fools?
