Regular signet reorgs

Okay, the logic I used above makes it too easy to go too far out of sync:

[
  {
    "height": 307525,
    "hash": "00000000ae6faa1ab0510c5c22bf6c3edb8f23c1800777ffa16631a9d9ae1c82",
    "branchlen": 163,
    "status": "valid-fork"
  },
  {
    "height": 307510,
    "hash": "000000085d2ea634de8d2cf13c03419f72876c4e811844bafbf8e44ea0c0a039",
    "branchlen": 148,
    "status": "valid-fork"
  }
]