Mine came loose, started misfiring badly, bike out of warranty, Ducati UK didn't want to know at all. Was only by posting on here and various US forums when someone emailed me, and said they'd had their Monster I believe repaired outside of warranty several times with this problem. I then passed this information onto Ducati UK, and within 30 minutes they honoured the claim funnily enough, even wrote me a nice letter
Bike went into JHP, turns out it would of cost me over £1000 in parts I was lucky the crank wasn't damaged.
I believe though it's every 12,000 miles, not 6,000 although the Bostrom did have it checked and retightened at 6,000 miles as stated on the service book by JHP.
Food for thought