By the headline of this thread the OP suggested that there might have been an UI, but he did not mention in the text what kind of UI this might have been. I understand this was an online tourney, so the only possible kinds of UI are chat or break in tempo, and I guess the OP would have told us about that if it occurred.
As he did not specify the kind of UI, it looks to me as if he wants to suggest that because strange things happened, there must have been an UI. I strongly object that. There is only an UI if it has been observed. If you assume an UI that could not be observed (e.g. by telephone), you just assume they are cheaters. But this should not be assumed without any evidence.
Another topic are undisclosed partnership understandings. But as long as it is possible to find some logic in the bids that can can be explained without assuming that E/W have a secret defense system against precision 1
♣, any accusation of this kind should be carefully avoided by the TD. If the TD is really suspicious he should ask Stephen Pickett's
database if such a call like the 1
♠ has occurred before when these 2 players played together.
Others already pointed out why all bids by EW were reasonable without knowing details of the hand in advance. I may add that the possibility that East may have
♦ makes it even more risky for West to bid them, because this might have led to a
♦ contract if North did not bid 3nt but simply pass and instead. If I were West and knew my partner's hand I would not bid 3
♦ here, as I cannot foresee that North will bid 3nt. The 3
♦ bid is only good if partner has not so many
♦ cards and the 3
♦ bid makes it impossible for opps to find their nice
♦ fit.
Karl
1♣ 1♠ 2♥ 3♦
3nt AP