I installed the Recuva demo, and it installed CCleaner on my computer, without asking me.
However innocent CCleaner might be, installing other software without permission is a hallmark of malware, and doing so has harmed my faith in Piriform as a company.
May I ask which website page you used ?
A link would be nice
If it was the official installer and the additional software was google or a vpn software (can't remember the name), that's how piriform keeps recuva and other software free (not demo) and there is plenty enough opportunity to refuse installation of bundled ware (as well as portable version, which has no bundle).