Is discrimination against residents always an Equal Protection violation?

I am following from afar the clammer over the abusive driver fees.

There is at least one case I've seen, dealing with a state's implied consent law, where the residents, or some of them, get a worse deal than non-residents. Here is the discussion in that case:

"The appellant asserts that § 5-65-205 also allows for enhanced penalties for an Arkansas resident who has a valid driver's license and prior convictions, but there are no enhanced penalties for subsequent offenses committed by a resident without a license or a nonresident. The statute does provide for different penalties depending on whether (1) the person is a resident of Arkansas with a valid state driver's license, (2) the person is a resident of Arkansas without a valid state driver's license, and (3) the person is not a resident of Arkansas. However, the Equal Protection Clause does not preclude all statutory classifications. Hamilton v. Hamilton, 317 Ark. 572, 879 S.W.2d 416 (1994). Indeed, we presume the statutes passed by the General Assembly are not unconstitutional and will uphold a classification in the face of an equal protection allegation if there is any basis for the classification. McFarland v. McFarland, 318 Ark. 446, 885 S.W.2d 897 (1994). A party challenging a statute must bear the burden of proving it unconstitutional. Beck v. State, 317 Ark. 154, 876 S.W.2d 561 (1994). The appellant has the burden of proving that the act is not rationally related to achieving any legitimate objective of state government under any reasonably conceivable state of facts. Reed v. Glover, supra.

We merely consider whether any rational basis exists which demonstrates the possibility of a deliberate nexus with state objectives, so that the legislation is not the product of utterly arbitrary and capricious government purpose and void of any hint of deliberate and lawful purpose. Reed v. Glover, 319 Ark. 16, 889 S.W.2d 729 (1994). It is clear that the legislature has created varying penalties for violation of the implied consent law; it is equally clear that possession of an Arkansas driver's license carries with it the implied obligation to abide by state laws pertaining to driving. It is also significant that residents of Arkansas who drive without a valid driver's license and nonresidents who drive while their driver's license or driving privilege as a nonresident has been suspended are subject to additional punishment. See Ark.Code Ann. § 27-16-301 and § 27-16-303 (Repl.1994). Section 27-16-301 provides it is a misdemeanor for any person to violate any provisions of the Uniform Motor Vehicle Driver's License Act; the act states that no person shall drive any motor vehicle without a valid driver's license. See Ark.Code Ann. § 27-16-602 (Repl.1994). Section 27-16-303 provides that any person whose driver's license or driving privilege as a nonresident has been suspended and who drives any motor vehicle upon the highways of this state is guilty of a misdemeanor. For these reasons, it cannot be said that Section 5-65-205, and its varying punishments, are completely devoid of a legitimate purpose."

Cook v. State, 321 Ark. 641, 647-649, 906 S.W.2d 681, 685 (1995).