Or they don't obey the rules and signs to stay away from the horses in the pasture.

In an effort to make sure they do hold up the referral fee would you have them sign a referral agreement?  

I just signed a subscription for a new property in March without incident. re: rate consistency in section 6.1 “The quality of the experience is based on a variety of factors such as calendar accuracy, Host response times and booking acceptance, rate consistency,”

And without a solid budget, you are even less likely to get a lender to sign off on the deal.The best way for many to get started is to find a friend or family member that has money and can invest in the deal for the lion share of the profits.  

We were told to buy lots and then sign contracts to build with Blacktip.

Yes, you can work on a subdivision, especially if you let the seller/lender know your intent, since some jurisdictions require that the lender of record sign the map before it gets recorded.

So we agreed on a price, shook hands and signed some papers.

Get as much understanding and disclosure as possible on the closing fees and escrows that will show up on the settlement statement - including stuff like prepaid interest ("stub interest"), tand and insurance escrow holdbacks, etc - biggest pitfalls we've seen are people not 1000% clear and aware of these things then getting very negatively surprised at the day of signing 

@Regina BaileyThe problem with Certified mail is the tenant has to sign for it.

Sign companies, plumbers, electricians, concrete, etc.