"You can't insta-delete [x]"
We'd like to be able to turn this message off, so that the tool just works normally on the disallowed material(s).

eg if onlyAllow: [1] and the user is digging 1 and 4, then the tool takes the vanilla amount of time to dig the 4, with no messages sent to the player.

The way ToolBelt is currently set up, the normal use of a tool with ToolBelt functionality is canceled. This is done at a lower level then any individual tool has control over. If a user has the ability to use a ToolBelt function at all (permission toolbelt.tool.x) then the normal use of that tool is canceled. Overall I like this consistency across ToolBelt, so I'm not sure how to handle this request.

I can definitely make the warning message optional, but that's not what this issue is really asking about. I'll have to think about this some more, please feel free to discuss this in further comments.

Possible alternative:
A configurable "repeatDelay: x" for different materials.

That way we could set the speed to a different/normal rate, for materials that we don't want to be instapicked.

This is now configurable in release 0.4. If you wish to suggest a change in the priority of certain print messages, please open a new bug on that issue.