This probably would raise suspicion and CBP will detain you, as will bringing no phone at all.
This is the EFF's statement regarding wiped devides:
We don’t recommend disk wiping as a border crossing security measure for most travelers. It’s a less common data protection technique than the other ones highlighted in our guide, which include encryption and minimizing data that you carry. Wiping your computer will make it unusable to you. Also, it may draw the attention of border agents, since it is unusual for travelers to carry blank devices with them. This may be of particular concern to travelers who are not U.S. citizens, who may receive more scrutiny from border agents. Again, you should consider your risks and security needs carefully before deciding how best to secure your data for border crossings as everyone’s individual risk factors and data security needs are different.
This is the EFF's statement regarding wiped devides:
We don’t recommend disk wiping as a border crossing security measure for most travelers. It’s a less common data protection technique than the other ones highlighted in our guide, which include encryption and minimizing data that you carry. Wiping your computer will make it unusable to you. Also, it may draw the attention of border agents, since it is unusual for travelers to carry blank devices with them. This may be of particular concern to travelers who are not U.S. citizens, who may receive more scrutiny from border agents. Again, you should consider your risks and security needs carefully before deciding how best to secure your data for border crossings as everyone’s individual risk factors and data security needs are different.
https://www.eff.org/de/deeplinks/2017/07/crossing-us-border-...