At the start of the pattern nod to the judge, that is to make sure the judge is ready and not still writing notes about the previous rider.
Most shows just have the pattern but can call you back for rail work.
Going off the pattern is often an automatic DQ but keep riding even if you realize you made a mistake because some judges will still use a rider that is only slightly off.
You are being judged but if your horse misses a lead then that goes against you.
Practice as many patterns as you can before attending the show. It just helps you and your horse become smoother about the process.
I love doing patterns because it is not about who spent the most money on the horse, it is about the hard work the rider has put into their riding skills. Plus, if going for a day end award many people do not do the eq and it is a great way to pick up points.
I always have my students do the eq when at shows.