Responsa for Moed Katan 44:4

אמר אביי גדול הדור רבי גדול הדור שעמו ר' יעקב בר אחא ואיכא דאמרי גדול הדור ר' יעקב בר אחא גדול הדור שעמו רבי

Now it seems correct if Rabbi was the 'great man of the generation' that was with him [with the mourner], we understand why [R'Jacob B'Aha]<span class="x" onmousemove="('comment',' D.S. and many other texts.');">⁵</span> refrained and did not bare [his shoulder and heart];<span class="x" onmousemove="('comment',' Out of deference to Rabbi who was the Nasi, and therefore for him it was infra dignitatem. This was no disrespect to R. Jacob's father, as this is provided for in the rules: 'And if they (one's father or mother) seem not important (enough) for (the baring) , he (the son) does lot bare himself even for his father or mother'. Sem. IX. It should be noted that R. Jacob's father was not a qualified Rabbi, and that if 'Rabbi' Judah, the Nasi did out of deference to R. Jacob b. Aha bare himself, it would cause adverse comment among those present at the funeral. On R. Jacob b. Aha's status, v. Shab. ');">⁶</span>

Teshuvot Maharam