An "expert" has no additional control over accepted answers, only the question asker can mark an answer as accepted (save for bounties). Therefore, the best you can do is provide what you believe the right answer is, and if you believe it's appropriate, leave a comment on the accepted answer briefly pointing out the issue someone might run into if they attempt to use that solution. It is the responsibility of the consumer of the information, to protect themselves from bad code by using all the information provided. There is no way you can force someone to read past the accepted answer, but if someone chooses not to, then they have failed to do their part. Your part is to provide a correct answer, and comment on flaws as necessary. Hopefully people viewing the question in search of a solution will look through multiple answers, see yours, and understand why it is the better solution. Additionally, hopefully they upvote your answer as well, so that it floats up right underneath the accepted answer.