Originally posted by jeallen01 with your computer &/or BT account - can't understand why they even "bother" as I ditched our BT service (including the actual phone cable) in the mid-1990's
They don't necessarily use a database and are unlikely to check whether you use BT or not. Many (likely most) scammers just call numbers at random or in numerical sequence. They say they are from "BT" (in the UK) or "Windows" because they are what most people use, and TBH the demographics are such that those not using them are on average likely to be more circumspect and less likely to fall for a scam anyway. Many older people use BT because of inertia from when BT was the only telco, or because they still believe in brand loyalty, and that they would be demeaning themselves to compare prices. My mother was like that.
On another forum discussing scammers there weare reports of companies that have several phones with numbers in direct numerical sequence. Each phone has rung in that sequence as soon as the previous one has been answered and put down again. Similarly I have fewer scam calls now that I live in a rural area than when I lived in a city, which I believe is because the rural area phone number prefix is much less populated by numbers in use than the city prefix is. A scammer will therefore find a higher percentage of hits from random dialling if they use a city code.