Banks spend a lot of time checking borrowers assets, incomes, savings account balances, car loans, verifications and loads of other not so relevant information when you consider that if a borrower of theirs tomorrow turns to the bottle, gets cancer, goes broke, loses his job and falls behind, none of that above stated information will matter more than the remaining real estate equity securing their loan. In a foreclosure situation as the lender you don't get his spous' income, his car, sailboat, savings account, or anything else but the property. So, in my opinion if you ever plan to be a lender or a subordinator it would make good sense to educate yourself as much as you can about the collateral. If the collateral offered in any real estate transaction isn't sufficient to protect ones interests, one should require sufficient additional collateral or simply refuse the offer. Yes, under all circumstances.
Subordination is always safe.
If a person knows exactly what the terms are of the loan they are subordinating to and fully understands their risks and knows exactly how all of the proceeds of any loan they are subordinating to will be disbursed to improve that property, then sometimes if they can make it profitable enough to themselves to off set some unavoidable risk, it can be beneficial to all parties. The property will be improved. The property will not be improved. They will have to take the property back in foreclosure. They could lose their entire investment.