That is, you can try to order the item, but the seller has no legal obligation of fulfilling it if they can proof beyond reasonable doubt that a mistake was made, and can return the money instead.
How can you prove something like that in court in this camera case?
For example, let's say you were just getting into photography and were window shopping by browsing around Amazon's site.
You run into a camera that has a 4.7 average rating with 3,000+ reviews and the example pictures that people were posting look great to you. You have no idea about camera specs but you see it for $149, so you buy it. That doesn't seem too unrealistic, especially not when phones cost $1,000. You could totally think "oh, well $150 for just a camera sounds about right".
Go look at the screenshots in the article it shows the prime savings at checkout:
>Prime Savings -$1,204.52
That is a pretty clear indication that "wow, this is astronomically discounted" which should reasonably clue any adult with their full mental faculties in to "something strange is going on here".
Admittedly, many camera enthusiasts probably knew the market rate for this sort of equipment - but the fact something has a 90% discount doesn't automatically prove it's mispriced.
This actually hit the spotlight recently in Spain as Dell advertised 1000-1800€ laptops for 29-35€ on their site. Many people bought, received the first AND the second email around 5h later.
If it wasn't for that second email, they could cancel the order no questions asked, but actually someone on their side said "yep, this order looks fine" and clicked confirm. Consumer associations are hitting Dell with all their force.
 In Spanish: https://www.eldiario.es/tecnologia/portatiles-Dell-clientes-...