Mmm.........not sure about that Richard. Enthusiasm takes many forms - I enthuse about my guitars and I enjoy playing them but I won't tackle a refret or rewire pick-ups or renew a truss rod and I most certainly would be unhappy if I bought a guitar with any of these items faulty and furthermore then be told "Go on fix it yourself, it's easy!".
To re-emphasise my earlier point - if the expectation is that the purchaser should rectify such perceived "minor" defects and he, through inexperience or clumsiness, screws something else up (or worst case scenario - there are other faults when the bonnet is lifted).....well that's a whole new ball game (as we have seen on these boards many times before).
In this case it's a simple agreement between buyer and seller to have the problem fixed by someone who knows what they are doing. If that has to mean sending it back then so be it, however I agree, for a watchsmith it's a 10 minute fix.
Let's not get too snobby about our pastime. There are some who will want to tinker with their wares but the vast majority won't and who are we to criticise because they don't know how to replace an o-ring or a canon-pinion for example.
JTB