Pete:
Just thinking out loud: Nice, but I'd skip "attaching" it to the spool. Both "ends" on the snap passed through a hole in the spool. Never then going to be "in the way" when the spool is spinning or maybe snagging..... I'd maybe attach the band to the line loop so as not to lose it. I use hair "ties" as line keepers that way on my spools.
Just thinking out loud: Nice, but I'd skip "attaching" it to the spool. Both "ends" on the snap passed through a hole in the spool. Never then going to be "in the way" when the spool is spinning or maybe snagging..... I'd maybe attach the band to the line loop so as not to lose it. I use hair "ties" as line keepers that way on my spools.