Retail Sales Tax for Oregon Residence

I was purchasing some items at my neighborhood Target here in Tacoma, WA and I noticed the person in front me me was not charged sales tax on their purchase.

As it turns out, many stores in the area do not charge sales tax to people who supply a Oregon State liencense when they make a purchase in Washington State. Providing ID from Puerto Rico, Guam, Delaware, and a few other states also work.

Oregon state of course does not have a sales tax, but Washington state does. I assume the theory goes that although the person is purchasing a product in WA state, he/she is an OR resident and thus not liable for retail sales tax.

I was wondering if this was a special deal WA may provide to OR residents in order to allow their retail stores to stay competative with OR retail establishments or of there was a law behind this.

Does providing an OR ID work at all stores in WA? Does it work at all stores in other states, say California? Or is this simply a convience Target provides to it's customers? I'd like to know. Thanks.

Following is the Washington law, allowing the store not to charge the sales tax to Oregon, etc. residents:

Sec. 82.08.0273 ITEMS SOLD TO CERTAIN NONRESIDENTS
Description: Nonresidents who reside in a state, possession or Canadian province which levies a sales tax of less than 3.0 percent are exempt from Washington sales tax on purchases of tangible personal property in Washington for use outside the state (e.g., not meals or accommodations). Residents of other states may also be exempted if their state of residence allows similar exemption for Washington residents, but no state currently qualifies under this provision.

Purpose: The intent is to enable Washington merchants, especially in areas along the Oregon border, to compete with merchants located in states with no or low sales tax.
Category/Year Enacted: Economic development; 1965. (A fee of $5 for a nonresident permit was eliminated in 1989; in 1993 only one piece of identification was required.)

Primary Beneficiaries: Residents of Oregon, Alaska, Montana, and the Canadian Province of Alberta. Also, the exemption benefits Washington retailers in border areas.