Question for the Landlord

I am genuinely considering leaving a calling card in the bars i go to review, perhaps just a business card of some sort, to demonstrate my presence but what use would this be to leave a calling card with a tip at a restaurant or bar. Surely it would be favourable to my interest to expose myself as a reviewer from the outset of the visit or even give  a bar advanced warning before my visit, after all is that what restaurant critics really do. It gets me wondering if that gives the critic a rose-tinted view on the venue. The experience becomes catered and most bars and restaurants are not flagged for the incoming presence of a layman from the street. I suppose I wanted to take this opportunity to ask landlords and bar owners how they would prefer to be approached, whether they would prefer to know that a reviewer was present or even if they wanted to know who it was.

Please feel free to post your answers in the comment box below and get in on the debate.