I think the only thing standard about RS232 is that the description contains the letters "RS" or "rs" and the digits "232", with or without space or dash. Beyond that, all bets are off.
Various creative people have found MANY uses for the "non-essential" leads when doing short distance communications. I designed a point-to-point signalling system for an Operator Services unit that needed a status signal added - but the copper cable between them and the switching office had no spare wires. My fix had one pair of wires doing double duty. Put in a point-to-point modem to carry the text communications to a terminal and used one of the "extra" control leads on the modems to turn the "overload" light on and off as needed. Simple, used available hardware and could be implemented in one day. But that's what the geeks in the "skunkworks" did: we got the requests when someone else said "That can't be done". 95% of the fixes were done using what was already available - but in a way the "can't be done" speakers had never thought of.
However, RS232 protocol is robust - at least when run with shielded cable between 25 pin connectors, although people have reported success at impressive distances using a few strands of barbed wire as their "cable". Bell Labs came in to investigate the source of a lot of voltage difference between the AC grounds on different floors of a multi-floor telephone switching office when the grounded shields of the long RS232 cables running between computers and terminals on different floors drew sparks when they touched the metal chassis of the 80 character by 20 line terminal they were connected to (40+ years ago). They planned to put an electronic long distance telephone switching machine (4ESS) in that building and the grounds/neutrals of the AC power between ALL floors needed to to be "clean" - have zero current flowing in them. Many months and $$$$$$ later, it was finally fixed.