> what if I'm in New York, but running on a JupyterLab system in Los Angeles?

In this case, it would be the responsibility of the JupyterLab designers to set the timezone of the kernel to something useful to the user.  In the case of a single-user kernel that would be the user's timezone, in the case of multi-user kernels - most likely UTC or something that the users can agree upon.  The location of the JupyterLab server should never be a consideration.

Setting the timezone is currently more complicated than it should be:

import sys, time
sys.environ['TZ'] = 'America/New_York'

but I don't think we can improve that before python gets an integrated timezone database.  For now, this is what you should do to make sure a remote system uses the timezone that you want.