What's the most unsafe MySQL configuration?
At first glance, I would look over

innodb_buffer_pool_size
innodb_log_file_size
innodb_log_buffer_size

To properly judge the first two values, you should run this query:
SELECT CONCAT(ROUND(KBS/POWER(1024,
IF(PowerOf1024&lt;0,0,IF(PowerOf1024&gt;3,0,PowerOf1024)))+0.49999),
SUBSTR(' KMG',IF(PowerOf1024&lt;0,0,
IF(PowerOf1024&gt;3,0,PowerOf1024))+1,1)) recommended_innodb_buffer_pool_size
FROM (SELECT SUM(data_length+index_length) KBS FROM information_schema.tables
WHERE engine='InnoDB') A,
(SELECT 2 PowerOf1024) B;

This will tell you the ideal buffer pool size for the give dataset in MB. The innodb_buffer_pool_size should never be larger that 75% of installed RAM.
As for the log file size, I have two suggestions (pick one)
Suggestion 1: Set the innodb_log_file_size to be 25% of innodb_buffer_pool_size
Suggestion 2: If you want to set the log file size based on that actual amount of log file writes per hour, see my Aug 27, 2012 post Proper tuning for 30GB InnoDB table on server with 48GB RAM and my Feb 16, 2011 post How to safely change MySQL innodb variable &#39;innodb_log_file_size&#39;?
As for innodb_log_buffer_size, you should max it out to 8M. The larger the innodb_log_buffer_size, the less flushing of transactions will occur.
EPILOGUE
Your original question was What's the most unsafe MySQL configuration?. The real answer to that is : a MySQL instance with no config file whatsoever !!! ;-)