I am not sure about there being a general rule, here, but Immanuel Kant famously got a great sendoff, as noted by Thomas De Quincy:

.... for a funeral such as Kant’s, one so solemn and so magnificent, the city of Königsberg has never witnessed before or since. The public journals, and separate accounts in pamphlets, etc., have given so minute an account of its details, that I shall here notice only the heads of the ceremony.

On the 28th of February, at two o’clock in the afternoon, all the dignitaries of church and state, not only those resident in Königsberg, but from the remotest parts of Prussia, assembled in the church of the Castle. Hence they were escorted by the whole body of the University, splendidly dressed for the occasion, and by many military officers of rank, with whom Kant had always been a great favorite, to the house of the deceased Professor; from which the corpse was carried by torch- light, the bells of every church in Königsberg tolling, to the Cathedral which was lit up by innumerable wax-lights. A never-ending train of many thousand persons followed it on foot. In the Cathedral, after the usual burial rites, accompanied with every possible expression of national veneration to the deceased, there was a grand musical service, most admirably performed, at the close of which Kant’s mortal remains were lowered into the academic vault, where he now rests among the ancient patriarchs of the University. PEACE BE TO HIS DUST, AND EVERLASTING HONOR!

Thomas De Quncy: Kant's Last Days

It is hard to imagine any professor getting such recognition now.