And for psychs, they are regulated and allowed. So using a psyche is not cheating (unless it is known a bid can be a psych and this is not disclosed) Bridge law 40;
C. Deviation from System and Psychic Action
1. A player may deviate from his side’s announced understandings, provided that his partner
has no more reason than the opponents to be aware of the deviation [but see B2(a)(v)
above]. Repeated deviations lead to implicit understandings which then form part of the
partnership’s methods and must be disclosed in accordance with the regulations governing
disclosure of system. If the Director judges there is undisclosed knowledge that has
damaged the opponents he shall adjust the score and may assess a procedural penalty.
2. Other than in C1 above, no player is obliged to disclose to the opponents that he has
deviated from his announced methods.
As for this (type off) bidding sequence, remember who did it. I used to regularly play against a partnership where we basically knew, we were very likely to be able to cash the first two tricks in the suit of the first control bid N/W player of the pair, very usefull knowledge

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As everybody has pointed out:
Whether deliberate or a mistake, departure from your agreements is legal (provided it's as much a surprize to partner as to opponents).
Edited to remove names as GordonTD requested.