This has never been a problem at my gym. I can see why it would be, as the colored gis usually show some experience and commitment to the style, but I've never seen this come up.
That said, it's probably an issue of where you train more than anything. You may want to check with your instructor, and not with the guys on the internet who don't know the specific environment your stepping into.
BJJ is a diverse world, and so alot of this stuff really is school-specific, just like the style of jiu-jitsu is school-specific. All we can offer you is insight into our own experiences and, as helpful as that might be, yours is probably going to be different.
Ya it never happened at my school either but I have read this on a lot of other forums and hear it from other people... just a possible warning I guess. I still think if a new kid showed up with a Black gi on people would definitely look at him weird and might possibly treat him different. The Bjj world is kinda sketch with a lot of politics and BS going on