I ve noticed with dismay on Nairaland that some car dealers hardly diplay the VIN or mileage of cars they intend to sell. Even when a potential buyer requested, some avoid displaying it. I don't know why?

Simple... Dishonesty.

thats because they are thiefs, or to be polite they are criminally minded.

If you are interested in the car, ask for the Vin and mileage.. If they remain secretive after that, then yes they are trying to hide the information for reasons that are not in your interest...
Disclosure of Vin and mileage is a must if you are trying to buy the car..
But also remember the dealers must protect themselves from people trying to copy the car ID by creating a fake title that checks at the department of Motor vehicles... Thieves have been arrested before operating stolen car sales where they create a false vin and title for the stolen car..they do so by copying the vin number off of legitimate cars and the mileage to put on the fake title documents so that when the title is checked by vin number,,it will appear on the public record but it will be two cars secretly sharing the title and one is stolen....

If they remain secretive at point of sale agreement, don't sign any agreement and kindly bow out...

Follow my car advertisements I don't hide any info....

Just to add to what others have said,time is also an issue. Let me use myself as an example. For almost 24hrs everyday,I usually have my phones in my hands cos I spend the whole day responding to requests and enquiries from clients on bbm and it goes on for the whole day,up till night. While at that,I'm answering phone calls and also attending to clients at the lot. By the time I'm uploading an advert,I'm thinking of making it as short and as precise,so I can do other stuffs. When I put out a detailed ad,it means I have time on my hands but at such times,I might necessarily not have the documents of the car right there with me,or be close to the car(usually at night). But if a client signifies interest in having the VIN,it's usually not a problem giving out sch info.

One also has to be careful with scammers online. I have seen my 2011 honda croostour which I advertised on NL for 5.7m,lifted and placed on olx for 1.5m. Recently,my 07 GX470 I listed on NL,was placed on olx for 1.7m. What do you think would happen if the scammer lifting my info from here,has access to the VIN of these vehicles? He would have simply placed it on olx,thereby making his advert look real as the pictures and VIN would match if investigated.

In conclusion,do not assume all ads without vin nos,were placed with the intent to decieve. Only when dealer is refusing to disclose such info after you have asked for it,can you conclude that.

@Calculusx, you are correct but as a dealer you usually show vehicles pre-purchase pictures and after repair pictures and still got buyers with no issues.
If most dealers will be honest, nomatter how high the mileage, nomatter the accidented condition, as long as the dealer is honest with his customer and has fixed the vehicle properly he'll still be patronized.
Honesty is the key here. I know we all want the best for less and the dealer has to make profit too to survive but truth won't hurt rather it brings more trust.

MANGAM: I ve noticed with dismay on Nairaland that some car dealers hardly diplay the VIN or mileage of cars they intend to sell. Even when a potential buyer requested, some avoid displaying it. I don't know why?

You can simply request for it.

Good day can you [ls help me check this car vin 1nxbr32e04z240135. thank you my email is bunny77ng@yahoo.com

https://www.nairaland.com/638733/free-vin-checks-reports

Karioska: Good day can you [ls help me check this car vin 1nxbr32e04z240135. thank you my email is bunny77ng@yahoo.com

https://www.nairaland.com/391212/free-vin-check-cars-usa

Karioska: Good day can you [ls help me check this car vin 1nxbr32e04z240135. thank you my email is bunny77ng@yahoo.com