I've never understood widely-held idea in US software circles which consists of the CEO wiping their arse on a piece of paper and calling it an EULA or T&Cs and this apparently makes the seller or service provider invulnerable to their customers. I suspect we're about to find out it's not true.
It doesn't always provide invulnerability, as my favorite copyright attorney explains in this video-
https://www.youtube.com/watch?v=byZHIoqi8oo
Where he goes through the T&Cs and points out that although they attempt to immunise themselves against any liability, they can't avoid some. So points out that negligence and gross negligence statutes still apply. Then goes through some existing case law where companies have been found liable, even though their terms attempted to avoid that liability. So basically it might be proven that ClownsTrike were grossly negligent by not testing the update before pushing it to their customers.
He also points out that the T&Cs may not apply to some customers. This is something I've dealt with in previous projects. Most standard T&Cs are essentially worthless and don't warrant that the product or service will work. No sane customer would agree to those terms, but the balance of power is very lopsided, ie an SME would probably have to just take it or leave it. Large customers have more power.
So ClownsTrike may be part of a bid/RFP for services. The bid document would set out specifications, and the bidders would have to be compliant or non-compliant with each requirement. If ClownStrike responds to a bid, that would form a contract and their standard T&Cs may not apply. Bidders generally want the client to accept T&Cs because that's just a lot easier. But on large bids, you go through the responses with internal/external counsel to look for stuff like this. Then it can get interesting, ie the bidder may refuse to vary their standard terms, or bid 'fully compliant' and then just accept their may be an SLA violation and eat the loss. Trickiest one is if the client demands consequential losses, which is then trying to negotiate that away, or insure those losses and limit liability to $X million etc. But that then means negotiating with insurers, who'll obviously want to understand the risk profile.
And negligence still generally trumps all of that. But given the extent of the outages, losses and publicity, I expect lawyers will be salivating over the opportunity to try for negligence, either in individual cases or as a class action.