The previous post quoted an example from Lindley Murray’s English Grammar to illustrate that restrictive relative clauses are not separated from the antecedent by a comma: A man who is of a detractory spirit, will misconstrue … (1795:164). Lyda Fens-de Zeeuw, a specialist on the subject of Murray and his grammar, pointed out that the comma that we do find in this sentence deserves a comment, too: it separates a so-called compound subject from a predicate. This use of the comma, she points out, was fully acceptable according to Murray (1795:160), but “is nowadays frowned upon”. Not to allow a comma between subject and predicate was indeed one of the first editorial rules I learnt from my colleague when we co-edited a collection of articles (my first) in 1991.
What gave rise to this proscription, and when did it arise? Do editors regularly encounter this usage? Are readers of this blog aware of this stricture?
Bridging the Unbridgeable 
I do not know what or when, but I do know that it is frowned upon, to the extend that it’s called “a stylistic tic” that one needs “to work on” (guilty!) or “a heavy spice to be used sparingly”.
Funnily enough, I just came across a status update on FB, accompanying a photo of a man named Jack, wearing a helmet. It reads: “Jack off on a motorcycle.” The lack of comma here cost the writer a number of teasing comments, as the pan was not intended and would have been avoided by a comma after the subject. Personally, I favour the comma, as I do spices:)
The update “Jack off on a motorcycle” rather invited the teasing it got. As it is, it will quite naturally read as an imperative sentence, starting with the verb ‘jack’. For the intended meaning, the sentence did not as much require a comma after the subject (which in its imperative interpretation does not have) as a main verb.
True, the verb though is often omitted in the context of photo captions (as in these examples, also from FB: “Us, by the pool”, “Mel, on the sofa”)