Is it true that arahants don't have sati?

A couple of months ago someone tried to convince me that arahants no longer have sati. He said that sati is like a raft in the sense that it should be given up as soon as the goal, arahantship, has been reached. To give more strength to his claim he also pointed out that sati is not one of the 10 parami (perfections). I myself think that his claim is absurd, I think that arahants have nothing but sati. But, I'm neither a scholar nor an arahant. So, I can be wrong. I also don't understand the link he makes to the 10 parami. Does someone have a reference or source from the tipitaka that would support or deny his claim without a doubt and put my mind at ease? And does someone understand the link he makes to the perfections?