If you create a text/font object, transparencies of objects between it and the camera do not effect it.
So you can have a plane that is 50% transparent in front of it, but the text will still be %100 visible
I have attached a demo file.
Questions:
TextTransparencyProblem.blend (74.3 KB)
That plane infront of your text seems to have no face surface on it, only 4 vertises? 
EDIT: Nevermind, transparency indeed seems to be acting weirdly and has no effect on the text.
perhaps this somehow can be “fixed” by converting it to a mesh? Perhaps it may be a “desired” visual property? Did you check if it’s “X-ray” (you can see it no matter how many objects are between it and the camera) enabled by default?
Yes, it can be fixed by converting to a mesh, but I happen to want it as a text object so I can change what it says.
No, it is not X-ray causing the problem.
dunno, perhaps try reporting it - seems nobody knows about it…?
In the meantime, here’s a possible alternative for you :
For GLSL mode:
http://www.tutorialsforblender3d.com/GameDoc/Text/Text_GLSL_Steps_1.html
For Multitexture materials mode:
http://www.tutorialsforblender3d.com/GameDoc/Text/Text_Multitexture_Steps_1.html
For Texture face materials mode:
http://www.tutorialsforblender3d.com/GameDoc/Alpha/Alpha_Steps_Texture_1.html
