The times we cleared Customs there the agent said please put all your checked bags onto the moving belt and was serious about that.
That is what one is required to do...
http://www.orlandoairports.net/arrive/arrive.htm
Personally, I avoid getting into any type of disagreement with Immigration and Customs officials. They can make life very difficult. (of course, at my home airport the Immigration officials know me very very well, but that is another story!)