As these two tuner types (DVB-T and DVB-C) are always integrated into one and cover the same frequency range, is the conclusion that every DVB-T tuner is capable of scanning DVB-C frequencies and vice versa appropriate?
ETSI report discusses fully about them. See these reports: "Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for digital terrestrial television" & "Digital Video Broadcasting (DVB); Frame structure channel coding and modulation for a second generation digital transmission system for cable systems (DVB-C2)".