Telling Prospective Employer you have an offer elsewhere

[ToothbrushMan]

Setting a hypothetical scene where you are out of work and land an offer with firm A and are yet to accept it or youve accepted it but have yet to start.

You 2nd interview with firm B (a role you much rather prefer) so at that second meeting would it be looked upon as arrogant to drop that into the conversation to let then know that if they want you they cannot afford to mess around or that at least put them on notice that youve proven you are worthy to get an offer elsewhere or do you just keep it quiet?

I am thinking - tell them as its a form of marketing yourself that you are the person they should hire and I dare say that provided its done right your confidence will come across in that meeting because youve taken back some control over the situation putting you on more even playing field than when you had nothing else in the pipeline ie ;-if you arent prepared to take me seriously at this stage and make me an offer somebody else will (or has).

Good idea or not?

[QuartzDad]

In my experience as a hiring manager it's always helpful to know where the candidates are in the process with other companies, can help expedite the approval process if needed.