At a minimum, help text should note this. This is true for things like addwitnessaddress especially.
{
    CWallet * const pwallet = GetWalletForJSONRPCRequest(request);
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 5)
        throw std::runtime_error(
            "listunspent ( minconf maxconf  [\"addresses\",...] [include_unsafe] [query_options])\n"
            "\nReturns array of unspent transaction outputs\n"
            "with between minconf and maxconf (inclusive) confirmations.\n"
            "Optionally filter to only include txouts paid to specified addresses.\n"
            "\nArguments:\n"
            "1. minconf          (numeric, optional, default=1) The minimum confirmations to filter\n"
            "2. maxconf          (numeric, optional, default=9999999) The maximum confirmations to filter\n"
            "3. \"addresses\"      (string) A json array of bitcoin addresses to filter\n"
            "    [\n"
            "      \"address\"     (string) bitcoin address\n"
            "      ,...\n"