Doubling to say "don't lead my suit"

One of my favorite bridge books is George Rosenkranz' Tips for Tops.  As well as being the inventor of the contraceptive pill and a fine bridge player, he's a real gentleman.  And his book is full of well-reasoned bridge logic that you don't find in most other books.

One of the agreements he recommends is a slight change from the normal precedence for leads against 3NT when your partner has doubled.  Most people play that if they have bid a suit and then they double 3NT, it says "damn well lead my suit: and if you're void, then at least apologize."  But what's the value in this silly agreement?  Assuming that you aren't actually void, weren't you most probably going to lead partner's suit anyway?  Remember that we don't use lead-directing doubles of freely bid games and slams to increase the penalty.  We use them to create a penalty where otherwise the contract was going to make.

So whenever possible I get my partners to agree to use a lead-directing double of 3NT to say "don't lead my suit."  It's possibly I had that agreement with my partner on this hand from BBO but, if so, I forgot (we don't play very often) and I apologize!

My hand was ♠A6 ♥K632 ♦J742 ♣Q54 in second seat (none vulnerable).  RHO and I passed, then LHO opened 1♣ and partner passed.  RHO raised to 2♣ (no alert).  This was passed around to partner who doubled.  RHO raised again (3♣) and I felt that my hand was worth a 3♥ call.  Two passes followed and now RHO bids 3♠!  LHO bid 3NT and it came around to me.  Should I double?

Obviously (so it seemed) 3NT was going down and I didn't particularly want a heart lead (not unless partner had an obvious heart lead himself).  Playing the way I prefer, I should double to suggest a different lead (a spade for example).  But I didn't double because I was worried that that would guarantee a heart lead.

As it turns out, no lead sets the contract!  However, against this particular declarer (I was allowed to win my ♣Q), a spade lead probably would have set it.  Or, if upon winning my ♣Q, I switch to A and a low spade, we would get 1♣, 1♥, 3♠ and maybe a ♦ (dummy's "spades" were 9752, while partner had QJT3).  I could even have set it by switching to a low diamond (or even continuing clubs) too.  Just so long as I don't woodenly continue hearts.  But naturally I thought partner's hearts were better, given that I didn't double.  You see how important these agreements can be.