Yeah i understand thats why i mentioned about the potential for spam message/calls. Is the landline number displayed in the store or is this only mentioned on tweedle?Every shop has a landline, if an employee is in the store then id assume someone would pick up the phone, if you so happen to know an employee at any dealership that's a luxury thing as you have a direct connection with said person in RP. However if you don't know any of the employee's on a personal level it makes no sense that you would be calling someone's private phone number, however it makes perfect sense for you to call the landline of the shop an enquire about what is is you want to buy.
(This is my personal opinion and NOT the opinion of staff)
Does the landline only accept phone calls? if so your not able to show interest in vehicle as you could be phoning when no one is around which may lead to a lose of sale to another dealership.
@Chris McCaini seen your suggestion and have already upvoted very good idea