People on work visas in the US are advised not to leave the country due to risks at border checks. Even traveling inside the US can be tricky. A Reddit user on H-1B visa shared their experience at checkpoints near the border. The two, with valid I-797 approval notices but expired visa stampings, visited White Sands National Park and Big Bend National Park. At White Sands Missile Range Museum, entry was denied to non-US citizens lacking passports. At one checkpoint, officers checked their immigration documents. One's soft-copy I-797 on phone was reluctantly accepted. At another, officers refused the soft copy and asked for a driver's license. They were then sent to secondary inspection for 10-15 minutes before clearance. The officer explained, "Soft copies may be rejected due to forgery risk. Even with a printout or original document, an officer may still conduct further inspection. It is legally required to carry immigration documents at all times." The Redditor added, "Border Patrol operates internal checkpoints near border regions, not just ports of entry. Officers were professional and respectful throughout. It is strongly recommended and legally required to carry immigration documents at all times, especially near the border." The Redditor only showed the I-797, but had a passport available if asked. An I-797 approval notice proves USCIS has approved the visa petition. It shows visa status, validity dates, and employer details if any.