That is, she must give her clients (the seller, if she has the listing, or the buyer, if she brings the buyer and represents the buyer rather than the seller) preferential treatment.

I will have to ask my clients if they got the same treatment.. 

My in-laws did that when they moved from Cupertino to Nevada City... same scenario  sold their little rancher for 1.5 and bought a really nice home in for 600k but the rancher they paid 30k for in the mid 60's  Best tax treatment around Is to Live in Vancouver Washington  work there .. pay no state income tax. property tax's are lower ( but they have a 1.7% sales tax when you eventually sell) then cross the bridge and pay NO sales tax on everything you buy in Oregon.. that's why you have major malls right across the river HUGE costo etc..

Will the treatment keep them away for good?

A REAL General Contractor gets very special treatment and they should, Even at lowly Home Depot every order over $2000 goes back to corporate in Atlanta for review, where they will knock off 5-25%.

BTW, if my tenants pay their rent on time for X number of years, do I now owe them special treatment?

However, I will say that LLC is not recognized in Canada and deemed a foreign corporation, resulting in unfavorable tax treatment.  

Didn't even need a treatment. 

@Greg JungeFrom the tax side your CPA/EA will have to start tracing disbursements to ascertain the tax treatment of related interest.Also if you take a draw from the HELOC, and put in a checking/savings account for a month or number of months while you look for a deal, it's not business interest like most would think. 

Now, there was a recent argument about taxes and different states tax treatment.