In parts of the
world with mud building insects the screw in hole is just the right size for
a mud builder to make it's home if the hole is left uncovered even for a
short period,

Yes,  That is why I did use the Lancair supplied lock pins but I tapped the first 1/2 inch of the hole, countersunk it and modified (reduced screw head diameter) flat head phillips screws to close out the hole when not in use -- This is OK for me since I only go on 6 or so "tie-down trips" each year.