Ha, well ... I still say that the "liability" song & dance is merely a polite way to say "no". Here's why I feel this way :
I own a company. So I carry a $1,000,000 liability policy on-myself (for our business operations). And can have any person or entity immediately added on, and/or given a certificate evidencing insurance. With nothing but a cell-phone call, and have the proof of ins. in someone's hand instantly.
And I've had several occasions, over the years, where : When I hear the "liability" excuse, I have gleefully told them : "Not a problem, let me provide you with proof of insurance, to alleviate that concern".
But guess what ?? They STILL say "no". And then move on to some other reason
However, one time when I played this card, it did work. An old town demolition contractor let me on the site , right while they were working, once I'd had my agent issue his office a cert. So .... I can't say it's *always* a lame excuse on their end