ITT lots of debate on whether AWS Account IDs are sensitive or not. To chime in my 2c; we've had this debate in multiple orgs with different security teams and the outcome has always been the same; they're not and it's counterproductive to your security posture to treat it as privileged information. Humans have a nasty habit of placing trust in people who have access to privileged information.
"Hi, this is Tom from AWS, I need to speak with you about your account 5923965523" - as a social engineering primer garners significantly different levels of trust from the target depending on whether the target perceives the account ID to be privileged information.
"Hi, this is Tom from AWS, I need to speak with you about your account 5923965523" - as a social engineering primer garners significantly different levels of trust from the target depending on whether the target perceives the account ID to be privileged information.