Yes, because She alone has the authority of Jesus to rule and to teach. To disobey the Catholic Church knowingly is just as much a sin as to disobey Jesus Christ or His Apostles.
Not even an out of context scripture for this, I see.
Becky .... this follows simple reasoning. Since Christ established His Church and gave it the authority to rule and teach. To disobey the Catholic Church (descended from Christ through His Apostles) is to disobey Jesus Christ Himself.
Did the people have to obey the Apostles?
Yes, because they spoke with the authority of Jesus, and therefore, to disobey them would be a sin.
"He that heareth you, heareth Me; and he that despiseth you, despiseth Me; and he that despiseth Me, despiseth Him that sent Me." (Luke 10:16)
If I warn you of something and you do not heed that warning and are injured as a result, who is at fault?