There are also heat tapes available to wrap pipes with and these can be plugged into a temperature sensitive device that only turns them on when the temperature is low.

I would call to police and ask about a restraining order if they persist.

But I am also sensitive to not bother him much outside of the tax prep knowing that his time is not free.

We have not really had a problem none the less we use regular lighting as well as motion sensitive lighting, and signs that say 'Smile you are on Camera' but there are no cameras.

Also consider that flips are also taxed at ordinary income, which can provide tax challenges as well.I would echo what others are stating and make sure you speak with a tax accountant, as this seems like tax sensitive  situation you are going for

Time-Sensitive Closings2.

to me your being to overly sensitive on this matter.

The HELOC analogy is very helpful.Those up-front fees/commissions, and the sensitivity of the product to finding a good agent to "design" a policy right, are big turn-offs for me. 

Remember also HELOC's have floating interest rates and you're dependent on a refi in 12 months and the fed's stated policy is to increase rates further, so you should do a sensitivity analysis on how high rates can go before the property no longer cash flows - if refi rates are 8% in 12 months, does the deal still make sense? 

Best way to underwrite these deals is to understand all the costs and potential (including what it takes to get there) along with time.Taking all of that and plugging it into a sophisticated proforma to evaluate the deal along with the risk (sensitivity analysis) to understand what the true value of the asset is.