I made a small Detroit Redwings cake for a wedding today - it's white marshmallow fondant and I used red buttercream to pipe the logo.  I just messaged the bride for pick up and noticed the buttercream might be bleeding onto the white fondant.  The buttercream crusted a few hours ago and the fondant was dry when I piped it.  What should I do?  How should I tell her to store it overnight to minimize the bleeding? 

AAt room temperature. Any condensation will just make the bleeding worse. It's hard to avoid bleeding with dark colors on white.

Should I tell her to try to keep it in an air conditioned room?  It's cool right now, around 68 degrees, but it's humid. 

AAt this point, since the buttercream has crusted, it should be fine at slightly higher temps.