Possible to install Anaconda without **any** default environment?

Background

I want to avoid ever "accidentally" working in a default environment.

I want to always have an equivalent to a requirements.txt or package.json file available, both to clearly separate one project from another, and so that I can easily look back to see what is installed (and what version of it).

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But I work primarily in the data science / analytics world, and primarily with Python.

As such, I use Anaconda, pip, and Homebrew (I have a Mac). It would be great to rely upon just one package manager, and many folks espouse one method or another to accomplish this. Truth is, as of now (Sep 2018), it's impossible to work in any breadth of topics and avoid at least some mixture.

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Setting my sights lower and more realistic, I simply want to make sure that there is no default environment wherever possible, to make it cleaner and easier to work on projects with others.

To my knowledge, there is no concept of an environment in Homebrew at all. Conda of course has environments, but it first sets up a default environment before you can create any others.

Question

Is there any way to install Anaconda without any default environment, so that I will always have to source activate <my_env>? If so, how do I do that?

Barring this, what are the best suggestions to accomplish what I want, which is to never accidentally work in an environment where it is unclear what my dependencies are, recognizing that I'm talking primarily but not exclusively about using Python?

(Please don't suggest that I should "just be careful" when installing packages. Yes, I understand that. But I am trying to pre-emptively be careful by making the wrong choices as difficult or impossible as I can. If I had no default environment, for instance, then pip would not even work until I sourced an environment since it would not be found in my normal environment.)

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