We always embroider our numbers (2015 excepted ). The last few years, a team mom had the machine, before that we sent them to a local embroider shop. They look great and hold up well. Actually we made an extra set in 2014 for 2015. So we are the ones responsible for no bumpers in 2015.
The 2016 rule was:
The bumper rules (as with all of them) are subject to change from year to year, but the 2012-2014 team number marking rules were very similar if not identical to 2016. ('5 is right out!)