is it possible to combine a validation error/warning in the same script for when the event is done in the UI versus a CSV Import or would the recommendation be to split these 2 events into different script?

They are different contexts, so yes you could (and probably want to) handle them differently. CSV is XEDIT and regular ui is EDIT, so check check the context and follow your different paths

thanks. can you do this in a beforesubmit script and throw an alert versus an error?

You certainly cant alert on the CSV path

ok

if you want to stop a record from being saved in the UI, client script is the more appropriate path

thanks

No, if you want user interaction with the save, use a client script. CSV/Edit mode can both live in the user event, just check

scriptContext.type

, these relate to the

scriptContext.UserEventType

enumeration (EDIT, XEDIT, CREATE, etc) and check

runtime.executionContext

and handle your desired behavior accordingly