I don't think we can assume anything.
The cost of a new one, given the OR volumes purchased, will be far less than the cost of requesting the return, receiving, handling, thoroughly cleaning, testing, and repackaging.
Bear in mind that most ISPs charge for the FTTC installation, and the modem cost is presumably part of that. I have certainly had no intimation that I shall have to return it at any stage. The fact that BT Broadband choose to swallow the cost in exchange for an 18-month contract doesn't alter that.
On BT ADSLx Total Broadband, were/are Home Hubs required to be returned on migrating out?
My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost.
Internet connection - IDNet Home Starter Fibre.
Live BQM.
"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.