MY GAC simply is in the regular lanyard holder. I folded it once, having the most important info (like my name, type of GAC etc.) on the outside and non imortant info (like rules) on the inside. For most CM's that is enough, I can just turn over the lanyard holder and they see what they need to see. Might also be because my GAC is a bit different and still requires some talking to CM at most rides to figure out which help works best. (it varies too greatly per ride and show and even day or time what assistance I might need to use one basic type of GAC).
I put my KTTW-card within that folded GAC, so it's still easy enough to reach when I need it. Although when knowing I won't need the GAC for an amount of time, I'll put the KTTW-card on top of the GAC and make sure the KTTW-card is showing, not the GAC. My lanyard holder lies down on my lap when wearing lanyard around neck, and I have noticed some glares, comments etc if the GAC is too visably for all to see. Don't want my mom to notice them (she's a bit touchy when it comes to my health and needs), so that way nobody sees it when not needed.