Swagbucks Surveys are a great way to earn points. So you wouldn't want to jeopardize your chances of taking them, would you?
The Swagbucks blog released it's reasons you would get flagged.
If you are improperly taking surveys you can be disqualified for the current survey you are participating in, your account will be flagged, and eventually your survey account will be deactivated. Swagbucks Blog.Among the reasons would be answering questions too quickly and and contradictory information, like answering one way in your profile yet stating another in a survey.
For more info and to keep from becoming an invalid participant click here.