You guys are overreacting.
Out of every business I've ever given my phone number too, NONE have ever called me.
Most of the time it's not a marketing scheme. Most of the chain stores record the transaction under your phone number as a convenience for the customer! If you lose your receipt, no problem, I'll look it up with your phone number.
That's how CSK was before O'Reillys bought them. Now at O'Reillys you are required to have a receipt, so in that case I don't see the sense in giving them your phone number, but I have and it doesn't hurt.
"I'd rather laugh with the sinners than cry with the saints." - Billy Joel, Only The Good Die Young