danny/emmy: Government (and businesses) can prepare for No Deal as much as it likes (and is not really preparing that much anyway, which is perhaps a serious mistake) -- but at some point Parliament is likely to assert its will and stop a No Deal exit. Whether that's accepting the Withdrawal Agreement in its current (or a slightly modified) form, or introducing some emergency legislation to extend or rescind A50 notification, I don't know, but it seems a pretty safe bet that the UK won't leave without a deal, on March 29th or any other date, at least not if Parliament is the final arbiter on this matter.
As I say, my preferred course of action would be for Parliament to reject this deal and then go on to cancel Brexit altogether, either before or after putting the question back to the people. My point, though, is that this really ought to be your preferred course too -- not so much the stopping Brexit bit, obviously, but if you hate the Deal but still want to Leave then your only hope is to force Parliament to do this by saying so a second time in a referendum.