At the balancing position, S knowing EW has 8-9 ♠ fit, and partner has 0-1 ♠ Therefore, partner is unbalanced with ♦ length, worst case is 1444 (and it depends whether you open 1♣ with 1444) So South should know that EW has major double fit while we likely have minor double fit. I am not sure how others will interpret Dbl here; I guess some of them may even think of PEN over T/O as S fail to act on first round. If that is T/O, it should be a minor T/O as the hand with ♥ length will likely to have negative Dbl in the first round. And one possibility balancing with 2NT which could not be natural as S fail to bid 1NT in first round. So I guess that make sense to interpret that as minor take out with 3♦ 4+ ♣. With 4+♦ we likely to compete in the first round already. The most important thing is: Whether you want to defend opp 4M - this is the ultimate question you ask when you evaluating the hand. If S think that is risky to push them to 4M, then you may not want to balance at this point.