unix_timestamp(string date, string pattern) UDF does not verify date is valid

hive> -- Date does not exist
    > select unix_timestamp('2017/02/29', 'yyyy/MM/dd');
OK
1488326400
Time taken: 0.317 seconds, Fetched: 1 row(s)
hive> -- Date does not exist
    > select from_unixtime(unix_timestamp('2017/02/29', 'yyyy/MM/dd'));
OK
2017-03-01 00:00:00
Time taken: 0.28 seconds, Fetched: 1 row(s)
hive> -- Date in wrong format
    > select unix_timestamp('2017/02/29', 'MM/dd/yyyy');
OK
-55950393600
Time taken: 0.303 seconds, Fetched: 1 row(s)