Yesterday I had my first experience of breaking a client site via GTM.

I was setting up GA event tracking on a JS-intensive site via jQuery functions in a custom HTML tag and accidentally included a reference to the jQuery API at the top. It was a conflicting version to the one already being referenced by the site and many of the stylings were dislodged- I didn't notice. There was panic for a morning.

Do you think situations like this will make people wary towards agencies managing the code through GTM? What precautions should I have taken?
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