What is the current state of the law on "reasonable reason" for an alien's failure to attend a hearing?

8 U.S.C. Sec. 1252(b). See generally INS v. Lopez-Mendoza, 468 U.S. 1032, 1038-39 (1984) ("[t]he respondent must be given a reasonable opportunity to be present at the proceeding, but if the respondent fails to avail himself of that opportunity the hearing may proceed in his absence"); United States v. Dekermenjian, 508 F.2d 812, 814 (9th Cir.1974). If, however, the alien can show "reasonable cause" for his failure to appear, he is entitled to have his case reopened and decided on its merits. See Matter of Ruiz, Int.Dec. 3116 (BIA 1989).