If a tournament advertises G/30, can either player demand G/25 d5? A minor controversy regarding advertised and allowed time controls has broken out on a chess mailing list I subscribe to. A one-day tournament scheduled for tomorrow advertises specifically as five rounds of G/30, and a member of the mailing list has claimed that any player can therefore demand G/30 (as opposed to G/25 d5), regardless of their opponent's wishes. The last time I played in this particular tournament, I asked the organizer if I could insist upon G/25 d5, and he said that it's my right to do so under USCF rules. Is this true, or does the fact that the tournament listing states G/30 (and doesn't mention an alternate time control) mean that I should actually be forfeited if I request a delay and my opponent refuses?
You don't have grounds to demand the time control you like. In practice I suppose that if your opponent agrees, you could get away with using whatever time control you both want as long as the game finishes on time, which is the main point the organizers care about.

One thing that the USCF rules do cover is what to do if the stipulated time control has a delay or increment and the only available clock doesn't support it. In that case the "base time" should be used instead.

However: did the advertisement say just say "G/30", or was it "G/30 d0"? Because according to the USCF, "If the organizer fails to specify an increment or delay time in the time control (which may be zero to indicate no increment or delay), the minimum recommended delay specified in rule 5E shall apply." The minimum recommended delay for 30 minutes is 5 seconds, so the way I read that, if it was advertised only as "G/30", you'd have grounds to demand G/30 d5.