It is possible you do remember brands you've seen advertised but just don't remember you saw an ad.

I remember a long time ago seeing a study that asked people if they had seen ads for the California lottery and if so what they remembered about them. They also asked people if they played the lottery and if so why they played.

What they found was that in the people who said they had not seen ads and in the people who aid they had seen them but could remember anything about them a large fraction of those who played gave reasons that were almost word for word quote from slogans from the ads.