It is interesting that they are paying attention to that, as the section on interactivity [1] brings "how to disable a cell" that would prevent its reactivity and anything that depends upon. With some careful placement, you can disable the automatic calculations. Another thing would be tuning the parameter for confirming before a long runtime. Set it to 50 ms, and only run "almost instant things".
[1]https://discourse.julialang.org/t/pluto-1-0-release/137296#p...