The FAA has been getting a lot of flak recently about being too cosy with the big Airline Companies! I'd guess that they're making a point!
I'd agree with groundbum about the risk vs impact of immediate groundings to facilitate inspection and if required, rework. However, I think that the 99% figure for take up would be overstated, if the PAX were informed about the fire risk.
Obviously, American Airlines maintenance should have done the job right, first time. So, I hope that they learn a lesson - I imagine that the cost of this, both financially and in terms of bad
PR will ensure that this is the case.