seems to be illustrating exactly what I meant. The UA string contains literal spaces. If you don't want to escape them you have to put the whole thing into quotation marks to prevent the space from taking on semantic meaning. You should also, ahem, escape the literal periods. Quotation marks don't turn off Regular Expressions.
There are applications of exactly as far beyond blank spaces.
I think your cat stepped on the keyboard.
...doesn't matter, I just don't want them to see the redirect...
They have to see something when they request the page. If you don't like or trust them, why don't you simply block them?
Edit: Back to OP:
SetEnvIfNoCase User-Agent .*rogerbot.* bad_bot
If you're neither capturing nor anchoring, the formulation .* is never necessary. It simply means "there may or may not be more stuff here".