secrec You should always assume the worst. If it can be done, you might as well assume it is being done. That is why systemic/blanket privacy features are important.
For example:
Will most apps bypass Cal*xOS' leaky firewall? Probably not. Does that make it reliable? No.
If someone's privacy/security depends on others not exploiting the holes they leave open - they are doing it wrong.
By the way. Most data only needs to be sent once at the first opportunity. The other usage stats like app launches, etc. are small data. Its 100% reasonable to assume that most apps that have analitycs, queue up lots of it.