How are IAM accounts impacted by default VPC?
If your AWS account has a default VPC, any IAM accounts associated with your AWS account use the same default VPC as your AWS account.

http://www.interviewquestionspdf.com/2017/01/how-are-iam-accounts-impacted-by.html
If your AWS account has a default VPC, any IAM accounts associated with your AWS account use the same default VPC as your AWS account.