The alltt package provides a simple verbatim-like environment (alltt), which
allows to apply LaTeX-commands and ignores all other special characters.
In other documentclasses the line breaks and 'special-character-ignorance'
are preserved, but not in tikzposter.
This is in particular annoying, because the R package knitr uses this package
for its automated code highlighting.
A solution to this might be to change the block and innerblock elements
to environments instead of commands. This is kind of LaTeX convention and e.g.
used in beamer, too.