Our normal import interfaces introduce keys with an effective timestamp of 0.

Importmulti introduces keys with a default effective timestamp of 'now'.

While documented it is highly surprising, especially because it contradicts the default on the rescan argument:

>     "rescan": <false>,         (boolean, optional, default: true) Stating if should rescan the blockchain after all imports

This means you can import a key and reasonably expect that it was rescanned ("I even set rescan true!") but have it not be rescanned, causing you to think the key had been unused and then you give it away and or destroy it and lose funds.

There are a number of other bugs in importmulti (mishandles pruning, needlessly forces the wallet to be unlocked when not importing private keys, etc.) which I am fixing, but I need feedback on this API issue.

Should the default become zero, with -1 special cased as 'now' or make timestamp mandatory? default it to the prune depth??

Should the result also tell us what it rescanned?
"Arguments:\n"
            "1. requests     (array, required) Data to be imported\n"
            "  [     (array of json objects)\n"
            "    {\n"
            "      \"scriptPubKey\": \"<script>\" | { \"address\":\"<address>\" }, (string / json, required) Type of scriptPubKey (string for script, json for address)\n"
            "      \"timestamp\": timestamp | \"now\"                        , (integer / string, required) Creation time of the key in seconds since epoch (Jan 1 1970 GMT),\n"
            "                                                              or the string \"now\" to substitute the current synced blockchain time. The timestamp of the oldest\n"
            "                                                              key will determine how far back blockchain rescans need to begin for missing wallet transactions.\n"
            "                                                              \"now\" can be specified to bypass scanning, for keys which are known to never have been used, and\n"
            "                                                              0 can be specified to scan the entire blockchain.\n"
            "      \"redeemscript\": \"<script>\"                            , (string, optional) Allowed only if the scriptPubKey is a P2SH address or a P2SH scriptPubKey\n"
            "      \"pubkeys\": [\"<pubKey>\", ... ]                         , (array, optional) Array of strings giving pubkeys that must occur in the output or redeemscript\n"
            "      \"keys\": [\"<key>\", ... ]                               , (array, optional) Array of strings giving private keys whose corresponding public keys must occur in the output or redeemscript\n"
            "      \"internal\": <true>                                    , (boolean, optional, default: false) Stating whether matching outputs should be be treated as not incoming payments\n"
            "      \"watchonly\": <true>                                   , (boolean, optional, default: false) Stating whether matching outputs should be considered watched even when they're not spendable, only allowed if keys are empty\n"
            "      \"label\": <label>                                      , (string, optional, default: '') Label to assign to the address (aka account name, for now), only allowed with internal=false\n"
            "    }\n"
            "  ,...\n"
            "  ]\n"
            "2. options                 (json, optional)\n"
            "  {\n"
            "     \"rescan\": <false>,         (boolean, optional, default: true) Stating if should rescan the blockchain after all imports\n"
            "  }\n"
            "\nExamples:\n" +
            HelpExampleCli("importmulti", "'[{ \"scriptPubKey\": { \"address\": \"<my address>\" }, \"timestamp\":1455191478 }, "
                                          "{ \"scriptPubKey\": { \"address\": \"<my 2nd address>\" }, \"label\": \"example 2\", \"timestamp\": 1455191480 }]'") +
            HelpExampleCli("importmulti", "'[{ \"scriptPubKey\": { \"address\": \"<my address>\" }, \"timestamp\":1455191478 }]' '{ \"rescan\": false}'") +
            "\nResponse is an array with the same size as the input that has the execution result :\n"
            "  [{ \"success\": true } , { \"success\": false, \"error\": { \"code\": -1, \"message\": \"Internal Server Error\"} }, ... ]\n");