As an experienced person in the 911 industry, there was some fraudulent calls, but the larger volume of non 911 calls came from a cell phone refurbishing company that would dial 911 as a testing procedure and then hang up. Do this hundreds of times a day, and you can see the issue with saturating 911 trunks with test calls opposed to real emergency calls. The ability to call 911 from an uninitialized mobile phone evolved from the same ability with a land line in a building to call 911 without service. The problem is that wireless phones are mobile, and can be difficult to track in a reasonable amount of time. Therefore is ripe for abuse and potential abuse. Some kind of identification would be ideal, but there is also burden placed on some entity to do that for essentially free, or as someone suggested having a low-cost SIM that would only call 911. That still doesn't prevent abuse just ties the caller/TN to an account or transaction paid by a customer. Still plenty of room for fraud if someone was determined to commit it.

Intrado does more than ALI. If ALI is down that isn't a problem for experienced dispatchers. Call processing was down e.g. call routing and that's the equivalent of routing 9-1-1 to /dev/null. Verizon is more or less out of the 9-1-1 business except in name alone.