As going there does not involve any official function or duty of their job, 100% of it better be coming out of their own pockets.
No congressperson is elected to fly around the world worrying how citizens of other countries are doing in their prisons.
How many media have asked these people yet if they have given any concern to their adding to climate change flying around the globe worrying about gang members.
How many media have asked why these people haven't anything more relevant to worry about?
I wonder how much you'd have to pay El Salvador to have these people mugged while there, their passports and luggage stolen, their flight home cancelled, then locked up on suspicion of spying?