I don't understand how the bundle me isn't safe? we have one and she seems fine to me and my sister used one for both her kids 6 years ago....
I never heard they weren't safe until recently
1. Most car seat warranties are voided if there is something between the child and the car seat that didn't come with the seat. Aftermarket products have not been tested with the seat and therefore could compromise the functionality of the seat and your child's overall safety.
2. Sometimes the slots on the Bundle Me do not line up correctly with the slots on the car seat, depending on your brand. This changes the way the straps fit. Though the straps might be tight, if they aren't on the child properly they can injure them if you were to be in an accident. Nothing is supposed to be between your child and the car seat.