After some googling, I recently ran `bitcoin-qt -zapwallettxes` on a 0.15.1 pruned multiwallet node in order to remove a stuck transaction from the transaction list, without fully understanding what I was doing. After running the command and realizing what I'd done, I was surprised to learn
1. The operation succeeded without warning despite the fact I was running a multiwallet configuration
2. The operation succeeded without warning even though I was running a pruned node. Meaning I now had to re-download and verify the full blockchain to get my wallets' transactions back
3. The software made no wallet backups despite the destructive nature of the operation

After some poking around in the code a bit it appears there are safeguards against 1 and 2, but they didn't trigger in this case. Maybe because my pruning and wallet options were being set via bitcoin.conf instead of the command line?

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strUsage += HelpMessageOpt("-fallbackfee=<amt>", strprintf(_("A fee rate (in %s/kB) that will be used when fee estimation has insufficient data (default: %s)"),
                                                               CURRENCY_UNIT, FormatMoney(DEFAULT_FALLBACK_FEE)));
    strUsage += HelpMessageOpt("-keypool=<n>", strprintf(_("Set key pool size to <n> (default: %u)"), DEFAULT_KEYPOOL_SIZE));
    strUsage += HelpMessageOpt("-mintxfee=<amt>", strprintf(_("Fees (in %s/kB) smaller than this are considered zero fee for transaction creation (default: %s)"),
                                                            CURRENCY_UNIT, FormatMoney(DEFAULT_TRANSACTION_MINFEE)));
    strUsage += HelpMessageOpt("-paytxfee=<amt>", strprintf(_("Fee (in %s/kB) to add to transactions you send (default: %s)"),
                                                            CURRENCY_UNIT, FormatMoney(payTxFee.GetFeePerK())));
    strUsage += HelpMessageOpt("-rescan", _("Rescan the block chain for missing wallet transactions on startup"));
    strUsage += HelpMessageOpt("-salvagewallet", _("Attempt to recover private keys from a corrupt wallet on startup"));
    strUsage += HelpMessageOpt("-spendzeroconfchange", strprintf(_("Spend unconfirmed change when sending transactions (default: %u)"), DEFAULT_SPEND_ZEROCONF_CHANGE));
    strUsage += HelpMessageOpt("-txconfirmtarget=<n>", strprintf(_("If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: %u)"), DEFAULT_TX_CONFIRM_TARGET));
    strUsage += HelpMessageOpt("-upgradewallet", _("Upgrade wallet to latest format on startup"));
    strUsage += HelpMessageOpt("-wallet=<path>", _("Specify wallet database path. Can be specified multiple times to load multiple wallets. Path is interpreted relative to <walletdir> if it is not absolute, and will be created if it does not exist (as a directory containing a wallet.dat file and log files). For backwards compatibility this will also accept names of existing data files in <walletdir>.)"));
    strUsage += HelpMessageOpt("-walletbroadcast", _("Make the wallet broadcast transactions") + " " + strprintf(_("(default: %u)"), DEFAULT_WALLETBROADCAST));
    strUsage += HelpMessageOpt("-walletdir=<dir>", _("Specify directory to hold wallets (default: <datadir>/wallets if it exists, otherwise <datadir>)"));
    strUsage += HelpMessageOpt("-walletnotify=<cmd>", _("Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)"));
    strUsage += HelpMessageOpt("-walletrbf", strprintf(_("Send transactions with full-RBF opt-in enabled (RPC only, default: %u)"), DEFAULT_WALLET_RBF));
    strUsage += HelpMessageOpt("-zapwallettxes=<mode>", _("Delete all wallet transactions and only recover those parts of the blockchain through -rescan on startup") +
                               " " + _("(1 = keep tx meta data e.g. account owner and payment request information, 2 = drop tx meta data)"));
    if (showDebug)
    {
        strUsage += HelpMessageGroup(_("Wallet debugging/testing options:"));
        strUsage += HelpMessageOpt("-dblogsize=<n>", strprintf("Flush wallet database activity from memory to disk log every <n> megabytes (default: %u)", DEFAULT_WALLET_DBLOGSIZE));
        strUsage += HelpMessageOpt("-flushwallet", strprintf("Run a thread to flush wallet periodically (default: %u)", DEFAULT_FLUSHWALLET));
        strUsage += HelpMessageOpt("-privdb", strprintf("Sets the DB_PRIVATE flag in the wallet db environment (default: %u)", DEFAULT_WALLET_PRIVDB));
        strUsage += HelpMessageOpt("-walletrejectlongchains", strprintf(_("Wallet will not create transactions that violate mempool chain limits (default: %u)"), DEFAULT_WALLET_REJECT_LONG_CHAINS));
    }
    return strUsage;
}
bool WalletInit::ParameterInteraction() const