If you saw distinct flaws in his routine and you felt it was hurting his performance. As a fellow magician, you should have talked to him when it was convenient and offered him some suggestions to improve. (That is, if you think you have some good advice to pass on).
If, however you were only unimpressed because you knew the secrets and werenâ€™t fooled. I suggest you bite your tongue and observe how the audience was responding to him. If they were entertained â€“ he did his job. (Gimmicks verses Slight-of-hand has nothing to do with being an entertaining magician. If the Audience enjoyed it, who cares what method he used?)
If you can get anything from this, you can learn what to do and what to do to enhance your magic.
I have seen professional magicianâ€™s performance in some examples where it was actually painful to sit through their show without wincing at how corny or bad the routine was. I did keep it to myself, however and noted what I definitely would not do for my show.
â€œIf this be Magic - Let it be an Artâ€