My concern is that any increase in already substantial state powers poses a twofold threat. Firstly, it makes future increases more difficult to oppose. Secondly, it risks falling into the hands of irresponsible future office holders.
I suggest that you wouldn't be able to trust your government with your text messages if you fell into one of the following three categories: freedom fighter, wrongly suspected of crime due to unchallengeable secret evidence and targeted for state-imposed restrictions without explanation, actual criminal (possibly under a homophobic, misogynistic or racist law).
I'm not sure about the banks, but maybe some of the above applies to them, too.
The New Zealand parliament has identified five "institutionalised checks on executive power". (They are a codified constitution, an elected head of state, a bicameral legislature, devolved powers and proportional representation.[0]) Only two exist in my country (the United Kingdom), neither of which is available to me, because one of our legislative chambers is unelected and (like the majority of the population) I don't live under the jurisdiction of a devolved legislature.
I don't understand your last sentence. By "insurance", do you primarily mean checks and balances? If so, which ones matter to you?
[0] See Table 2 on this page http://www.parliament.nz/en-nz/parl-support/research-papers/...