That was my first time visiting the UK.
I told them I intended to work on my company and they weren't bothered by that. They were mostly concerned that I didn't have a job elsewhere that I would have to go back to.
But you are right, it is a matter of luck.
Getting a visa may save you a lot of trouble. You really don't want to spend a night in a California immigration facility with MS-13 gang members [1].