If you were allotted a college in the second round of KCET counseling but did not join, you are not banned from participating in subsequent rounds or future KCET counseling, provided you follow the official rules. KCET allows candidates who do not report to the allotted college to participate in later rounds, but the allotment of seats in future rounds may be affected because some colleges may have fewer vacant seats remaining. It is important to ensure that you complete all required steps in the counseling portal, such as confirming your willingness to participate in the next round, and to check the official KCET guidelines for any specific conditions regarding non-joining in earlier rounds. Failure to follow the portal instructions could affect your eligibility, but generally, not joining a college in a previous round does not result in a ban.