I am a consultant juggling many travels for clients, some arranged by my client's travel office, some by myself. My clients are often competitors, and I try to be discreet and objective, adhering to my confidentiality agreement with each client to not cause trouble for myself and believe to date I have been successful doing so.

I was asked to do an on-visit consultation for client-1 who arranged for my ticket SLC-city A on D-D/M/Y

Subsequently, I was requested to do a consultation for another client-2 in City B during the same days I already had a ticket for city A, and not having enough information to know which one I would end up going to, I booked a refundable ticket SLC-city-B - returning to city-C where I already had another appointment.

Well this morning I received the following email from my client-1 contact stating:

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Hello Flying-Duck

We issued your electronic ticket for the on-site consultation at our facility in [City A] as agreed to be done on D-D/M/Y

Our travel department received a phone call from Delta this morning advising us that you had booked another reservation from D-D/M/Yfrom Salt Lake City to City-B and back to City-C (not SLC)

Delta informed us that the City-B ticket was just booked yesterday and you
do have today to void that ticket out without charge.

Please advise me you are still planning on coming to our facility in [City-A] from D-D/M/Y or not
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This is forcing me into an awkward discussion with client-1 I was not prepared to have now, as the "D-D/M/Y" are two months away. Further, by the nature of what I do, and the scarcity of facilities within our field, Client-1 now know exactly who I consult for ikn city-B, which I did not particularly wanted to share with them as they are competitors, creating a risk of me losing client-1

I feel Delta has grossly breached my confidentiality here causing potential damage to my livelihood by revealing a reservation I personally made, to a third party without my consent and without telling me.

I obviously never want to have this happen again (as I am sure some here as well would not) and I weighing where to go with this and to whom in Delta I should address my complaint - if anyone has ideas, I am all ears.

I am not looking for compensation at this point - but in theory I wonder whether I should consault a lawyer if I do lose client-1

It sort of reminds me of a promotion American Airlines did decades ago: They had a promotion where business travelers were given a free ticket for their spouse to bring on their trip, with some genius in marketing coming up with the brilliant idea of sending a "thankyou letter" to the spouse. You can guess what happened, many unhappy spouses and subsequent divorces later, (and I am sure flaming complaints to AA) AA had to quickly retreat from this idea!!
But seriously, I don't see the breach of confidentiality Delta committed on my behalf potentially not having similar potential dire consequences (as it may have for me)