As per the pricing page, looks like you _do_ need support plan:
"AWS Shield Advanced is available to customers who are enrolled in either the Enterprise or Business Support levels of AWS Premium Support."
"AWS Shield Advanced is available to customers who are enrolled in either the Enterprise or Business Support levels of AWS Premium Support."
Look like I'd need to pony up >1k/mo on top of 3k to get access to the service then...
So if you get hit by DDOS, you can't just pay $3,000 and hope that DDOS is gone within a month. Looks like you have to sign up for a year's worth of protection.