Violin plots of the S/N of the spectral lines considered in this study, with the S/N defined as f_ℓ(θ)/σ_a,ℓ. The EMIR lines are displayed in blue on the left, while the [CI] and [CII] lines are shown in orange on the right. Top: S/N distributions for a loguniform distribution on the full validity intervals on the physical parameters. The considered line filter only keeps lines that have a 99% percentile S/N greater than 3. This threshold is indicated with the horizontal dashed black line, and the actual 99% percentile S/N is shown with a short black line for each line. Bottom: S/N distributions in an environment similar to the Horsehead pillar, for the same lines. The lines are ranked by decreasing median S/N, indicated in red.