In some cases, I would like to show non-alarm state thresholds, which hiding alarm thresholds. See this competition data chart for an example. The greyscale thresholds are not alarm states. Instead, they are shown to illustrate the thresholds below/above which teams earn full, partial, and no points. Showing the true alarm thresholds (for things like sensor errors) would be confusing to the user, so I usually choose to hide them.