Aircraft refuelling during other aircraft's HF operation on the ramp has presumably - hopefully - been safety audited.
The HF transmission from your own aircraft is less likely to cause problems to your own aircraft because there is a conductive electrical path between your own HF system and your aircraft structure to equalise any electrical charges.
The problem can arise when two conducting bodies are not electrically joined - potential differences or static charges can arise. This is why your fuelling tanker connects an 'earth' wire to your aircraft before connecting the fuel hose: it forces both aircraft and tanker to the same electrical potential so there is no potential difference between the two, which could otherwise cause sparks and possible ignition when the fuel hose is connected and disconnected.
Two aircraft side by side on the ramp are not electrically connected to each other, and they have insulating rubber tyres, so a potential difference could arise - for example by one aircraft using a high power RF transmitter. As I say, hopefully, this has been considered - I always understood that HF and RADAR etc should not be used on the ramp, i.e. in close proximity to other aircraft.