I don't see the problem, unless you're getting emotionally attached to the property or making that deal. 

They probably charge more for personal residences since it's a more emotional purchase.

The people you're marketing to generally aren't in a difficult spot financially, and the only way they would sell to an investor is if they're going through divorce or some difficult emotional situation. 

The no phone line made communication with them a very slow process, and if your personality type is like mine and you are moving at a fast pace, then this also will be frustrating.

Sometimes I work with investors doing their first few flips and they get an emotional attachment to the property and this can cause them problems.  

Over communicate, great customer service and transparency in billing.  

Stay on top of the transaction and communicate the good or bad news and quickly as possible.

I did my best to communicate to the seller every step of the way and also footed the bill for some of the expenses he acquired, after all it was most important to me to look out for the seller and get him out of his difficult situation. 

Michael (I'am not a lawyer) the issues lie mostly in how you communicate with others and the way you position yourself (law states that a person cannot basically perform marketing, renting , anything that a realtor would do for others.  

Lawyers generally like to use boilerplate language and its often the paralegal that does your work, but your needs might be specific and if you know what your needs are and can communicate accurately to them.