Question about wholesaling

[Tyler Austin]

What prevents your end buyer from waiting out your option period and going direct to your seller? 

This implies that there is an option period - isn't there? To rephrase my question, if I put a house I intend to wholesale under contract for $100k, and find an end buyer who agrees to pay $130k, what prevents said buyer from doing a little digging and contacting seller and waiting out whatever option period me and seller agreed upon and saving $30k? In an unlicensed transaction, what recourse do I have to prevent this? Do I just not tell them the address? This is a hurdle I'm facing I still can't figure out. 

I'm in Austin, from DFW, and am licensed in TX.