I guess this falls in line with npm run -ws --if-preset <command>, because at the moment if I define a task on turbo.json as below:

turbo.json

{
   "pipeline": {
     "dev": { "dependsOn": ["build"] }
   }
}

package.json

{
   "name": "@scope/a",
   "scripts": {
     "build": "sleep 10"
   }
}

And then call turbo run dev, even though @scope/a doesn't have a script called dev, it will still run its build step and delay the process 10 seconds unnecessarily here.
So the idea would be that, since that the build script is not dependent, nor necessary for the execution of the dev task, we could either make that a default and skip unnecessary tasks or allow turbo run dev --if-present to be defined.
Hopefully I am not overseeing anything vital here 😃