After the drunken debaucheries at Varro’s villa, Antony made his way back to Rome, shut off from the world in his litter. For a high magistrate of Rome, whom everyone wants to meet and greet, travelling behind closed curtains was in principle a violation of socio-political etiquette, not least since it humiliated the inhabitants of the townships located en route who were keen to see (and curry favour with) the representative of Roman power. There may of course have been perfectly good reasons for an official not to interact with the local population, such as the need for speed or ill health, but a closed litter also reminded people of a funeral procession with the corpse shielded from sight — and this is the association Cicero activates for invective purposes here. Commentators refer to a story attributed to Gaius Gracchus found in Aulus Gellius, Noctes Atticae 10.3.5, to illustrate the point about travel habits and the expectations and dynamics that informed face-to-face encounters between Roman magistrates and locals: 

Item Gracchus alio in loco ita dicit: ‘Quanta libido quantaque intemperantia sit hominum adulescentium, unum exemplum vobis ostendam. his annis paucis ex Asia missus est qui per id tempus magistratum non ceperat, homo adulescens pro legato. is in lectica ferebatur. ei obviam bubulcus de plebe Venusina advenit et per iocum, cum ignoraret qui ferretur, rogavit num mortuum ferrent. ubi id audivit, lecticam iussit deponi, struppis, quibus lectica deligata erat, usque adeo verberari iussit, dum animam efflavit.’

[Gracchus also in another place speaks as follows: ‘I will give you a single example of the lawlessness of our young men, and of their entire lack of self-control. Within the last few years a young man who had not yet held a magisterial office was sent as an envoy from Asia. He was carried in a litter. A herdsman, one of the peasants of Venusia, met him, and not knowing whom they were bearing, asked in jest if they were carrying a corpse. Upon hearing this, the young man ordered that the litter be set down and that the peasant be beaten to death with the thongs by which it was fastened.’]