the use of rhubarb as a row or rumble is attributed - - -
My apologies for the delay, ladies and gentlemen. It has taken me a while to get round to this thread.

I was totally unaware of the belligerent connotations for "rhubarb". It puts a somewhat different slant to my soubriquet, does it not?
I was aware of "Hey, Rube" as an alarm call - I had thought among fairground folk, but that was from my hazy memory.
I read a wonderful short story about a couple of retired jugglers (so they were circus folk, weren't they?) who kept a store out in a lonely part of the mid-west USofA, who were invaded by a bunch of crooks who used the place as a HQ. The old couple overcame these thugs bu putting on a juggling act for them, using tins cans from the store shelves. At the shout of "Hey, Rube!" from the man (of course ) they started to hurl the cans at the crims, causing damage and havoc, disarming them and generally conquering all before them.

Highly unbelievable, but the sort of thing that you wished would happen.