remove warning for pol_convention in uvdata and uvcal

src/pyuvdata/uvcal/uvcal.py

@@ -1653,13 +1653,6 @@ def check(
             check_extra=check_extra, run_check_acceptability=run_check_acceptability
         )
 
-        # Check consistency between pol_convention and units of data
-        if self.pol_convention is None:
-            warnings.warn(
-                "pol_convention is unset. This leaves the "
-                "convention ambiguous. Consider setting pol_convention to 'sum' or 'avg'."
-            )
-
         # then run telescope object check
         self.telescope.check(
             check_extra=check_extra, run_check_acceptability=run_check_acceptability

src/pyuvdata/uvdata/uvdata.py

@@ -2215,13 +2215,7 @@ def check(
         logger.debug("... Done UVBase Check")
 
         # Check consistency between pol_convention and units of data
-        if self.vis_units != "uncalib" and self.pol_convention is None:
-            warnings.warn(
-                "pol_convention is unset and the data is calibrated. This leaves the "
-                "convention ambiguous. Consider setting pol_convention to 'sum' or "
-                "'avg'."
-            )
-        elif self.vis_units == "uncalib" and self.pol_convention is not None:
+        if self.vis_units == "uncalib" and self.pol_convention is not None:
             raise ValueError(
                 "pol_convention is set but the data is uncalibrated. This "
                 "is not allowed."