awk '
BEGIN { FS = "\t" }
NF > 0 && NF != 2 && NF != 3 {
	printf("%d: %d fields: %s\n", NR, NF, $0)
	next
}

$1 ~ /[][]/ || $2 ~ /[][]/ {
	printf("%d: includes brackets: %s\n", NR, $0)
	next
}

NF == 3 && $3 !~ /[][]/ {
	printf("%d: no brackets in $3: %s\n", NR, $0)
	next
}

' "$@"