There are definitely chancers out there. If you find a reliable service provider who you trust, stick with them. I've been using the same MOT chap for 20 odd years now, bikes and cars. I know him, he knows me. I know if he finds anything it is genuine. I often mention things I'm aware of for him to check before a test, stuff I know needs doing at some point but haven't got round to, he passes judgement.
In a similar vein ......
A neighbour had a problem with a Ford Ka not starting last year. I found the 11 year old battery was at about 4V, I charged it and got a start, checked charging voltage was OK and this got them where they wanted to go that day. I got a new battery for them and fitted it. I was sure they had left something on to drain the battery, an interior light or something, but they'd had their money's worth from the old battery anyway.
I did a quick check of things for them last week (tyres at between 14 and 27psi, shoukd be 32!), checked fluids and noted a new RAC branded battery. They've obviously had a flat battery again and the dear RAC chap helpfully advised them a new battery was required to replace the 12 month old Yuasa which was almost certainly perfectly fine (if flat), no doubt worrying them with the warning that if they get the same problem again the RAC won't come out unless they have a new battery. Kerching. I didn't ask what the story was for fear of embarrassing them, but it's the last time I fit a new battery for them, it's now up to the RAC.