Funny. I attended a creationist convention ('92 if recall correctly, it was at William Jennings Bryan College in Dayton, TN). Even outnumbered in the midst of hundreds of creationists, I never concealed my paid-up, card-carrying membership in the evo-cabal, nor did any of the 4 or 5 other evilutionists present. I doubt, in fact, if anyone there was unaware of our affiliation.
I also used to regularly attend meeting of a local creationist organization, sometimes with other evolutionists. Again I never knew then (or at any other time) of any failure of acknowledgment as you describe.
I was speaking from personal experience. Have yet to meet face-to-face an evo cultist.