there's a long road from "I'll buy from you but don't forget that I retire in 5 years' time, I hope there's a cushy job waiting for me" to "I'll buy from you, here's my bank account, make me a consultant wink wink"
Sole source contracts happen all of the time. Where it becomes murky is if the contracting officer ends up retiring his government job and takes a highly paid job with vendor.
