I'm not sure it works like that. You may get away with it, assuming the lawyer never reveals your intent, but this sounds a lot like the "security" extortion rackets of the mob:

"Hey thought you should know, my 'security' company is currently for hire for businesses around town. We heard through the underground grapevine that a lot of folks may lose some product in their bodegas next month. Anyway, nice to introduce you to my 'security' business -- have a great month!"

If you revealed that your true intent was blackmail, and that's what this is, to your lawyer or anyone else then I imagine the intent in combination with the act is enough to nail you.