I don't know if anyone else has had any problems with this, but I thought I would add mine just in case it happens to someone else. There was recently a network outage here in the southeast US through Verizon. When everyone around me was getting their coverage back my poor Nexus wouldn't reregister on the network. After, factory reset, flashing back to stock, reflashing every radio I could find, and talking with Verizon support (they were extremely helpful) I could not get the problem fixed. One call to Motorola and after describing my problem they issued a RMA and replaced my phone under warranty. So, long story short, if you have problems with your SIM card it might very well be the SIM tray. The speed in which they replaced my phone, and lack of simple support steps to walk through makes me think this might be a very common problem.