I'd want to see the entire auction. One of Jeff Goldsmith's Imperious Rules:
Quote
If you reverse into a 3-card (or shorter) suit, rebid your original suit as soon as possible or partner will assume you have four in the second suit.
I agree with most - it's hard to make a GF 1-minor suit rebid in Acol (or anything else for that matter). IIRC, the other "traditional Acol" way of showing this hand is 1
♣-1
♦; 3NT (showing a long (semi-)solid club suit and not enough stoppers for an initial 3NT). He may not know that - he may believe that *you* do not know that. But if after 3
♦ he bid 4
♣ and after 4
♦ he bid 5
♣, you should start to suspect. After 1
♣-1
♥; 2
♦-3
♦; 3NT-4
♦; 5
♣ I can see it being more difficult to "get".
OTOH, do we need to fake a reverse with this 16-count? If partner passes 3
♣, are we going to be upset? Well, it's arguable - but probably, yeah. We're going to have to be off 5 tops or we only get 7-and-the-stopper. I don't say 3NT is a lock, but there are certainly a number of hands that will pass 3
♣ where it rolls.
OTGH, reversing into a 3 card suit with a pickup is almost certainly an "even if it's 100% clearly their fault for not getting it, it's your fault for bidding it" situation. Were I North, I would have apologized, "Sorry, partner, I thought I could keep control of the auction."
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)