This is not necessarily true. First of all, not all games go on sale. Secondly, it is not a bad idea to advertise that your game will never go on sale. It is a reassurance to your customers that buy your product at full price that they will not see the game go free or $.99 the next day. I believe Starbase Orion has done this. $7.99 game, had an intro sale and stated it would never go free, and has never had another sale. Has been in top 200 consistently. Lastly, I have no idea of the thought process of people who steal, but I doubt a marketing strategy would be developed around them.
Be warned most of the telltale adventure games play very badly if at all on the touch 4th gen even tho they say they're compatible.... I bought all the monkey island games in an earlier sale but they're virtually unplayable.
Got walking dead complete for $5.00 when it was on sale a couple of weeks ago on playstation plus. They are having massive sales this month.