So, Piriform just proved themselves to be a bunch of f***ing a**holes: installing Google Chrome via a kind of backdoor, without asking for explicit consent.
That's 1 customer less ... and you can be damn sure I'll vilify Piriform on each and every forum I'm a member of.
The option to install bundled software is opt-out on the first page of the installer, you most likely did not see it because it is there. The bundles are what keeps the free version of ccleaner (and other piriform product) existing. A way not to get the offers is to unzip the portable version over your current version and deleting the file portable.dat from the folder.