If the commissioner finds that a taxpayer designs quickly to depart from this state or to remove therefrom his property, or any property subject to any state tax, or to conceal himself or his property, or such other property, or to discontinue business, or to do any other act tending to prejudice or render wholly or partly ineffectual proceedings to assess or collect such tax, whereby it becomes important that such proceedings be brought without delay, the commissioner may immediately make an arbitrary assessment as hereinbefore provided in section 54:49-5 of this title whether or not any report is then due by law, and may proceed under such arbitrary assessment to collect the tax, or compel security for the same, and thereafter shall cause notice of such finding to be given to such taxpayer, together with a demand for an immediate report and immediate payment of such tax.