Re: requesting fire service support.
If an aircraft requests fuel dump, then landing will be near max weight. Irrespective of cause, there is usually going to be a serious reason for this - technical, medical, etc. So:
- What are the disincentives on a crew where they would decline fire service attendence beyond, I dunno, not wanting to bother them
- What are the disincentives on ATC in respect of "our airport, our call", telling the inbound "we'll have services on hand" for max weight landings. Would it really be a significant imposition at an airport like SIN?