I am looking at a older Knabe concert grand which was "totally rebuilt" about 20 years ago. My concern is it has not been tuned in 15 years and the seller is reluctant to have a tuner come in. I advised the person i could not buy a piano without it being checked by a tech. They even offered to lower the price if i bought it without tuning it but to me that is a red flag. Am i being too cautious?
One obvious check you can make is, "Is it in tune with itself, whatever the pitch happens to be". I assume if you want to buy a concert grand piano to actually play it, not as a piece of furniture, you should be able to judge that for yourself - or you would have some musical friends whose judgment you can trust if you don't feel confident in your own ability.
If it is, then there's probably not much to worry about at least so far as the strings and soundboard are concerned. If not, you may be buying some very expensive firewood.
Note that the manufacturer's price for new Knabe concert grands range from about $30,000 to $150,000 depending on the size. A good quality 20-year-old rebuild would be worth a significant fraction of that (say 25% to 50% IMO). That is based on the plausible assumption that either it hasn't been played at all for 15 years (and therefore it won't have been worn out!) or else it has stood in tune well enough to satisfy the owner for all those years.
If the asking price is way below those numbers, either the seller doesn't know what he/she is selling, or you may be buying junk.
If they won't let you tune it, get a professional to value it "as is" at your expense. Since the pro will be working for you, he/she won't tell the seller what the valuation is. If they won't agree to either tuning or valuation, the best advice is probably to walk away!!
This sounds really awkward...
Shouldn't the seller have it tuned before hand for people to try and play? He would loose the deal because he would not spend a 100$ to tune it?
You'll find other great opportunities I'm sure.
Most important of all: would you buy again from this seller? Do you trust him? Wouldn't you like to buy from people you trust?
The reason for not letting you check it is not clear. They either know it's bad or are just ignorant of the importance of the procedure.
A tuner friend of mine always says checking's a must with second hand pianos because a tech can immediately (using a special key tool) tell whether 'the instrument will remain tuned or it will be untuned next week/month', so for him pre-sell check is often not about tuning but about how long it will REMAIN tuned.