With respect, insurance has nothing to do with it. This is down to flight crew and perhaps their engineers.
If operating privately, you have no option but to warm the aircraft up with available resources and hope it works...
If operating commercially: Prior to despatch, consult the MEL. If it allows you to operate without ITT indication, you may continue (though I would still speak to engineers). After despatch, consult the QRH or equivalent.
Either way, balance your own thoughts about flying a very fun little jet with the fact that it's not a robust aircraft, and just isn't up to a lot of the jobs asked of it. Cold weather starts are one of them.
...oh, and always check by hand that the N1 stage rotates properly prior to start in low temperatures or after a significant period parked, or you will be in deep and costly poo. It's OK to walk on the inboard sections of the wing to access the fan - see the manuals for details, but basically the structure under the 'walkway' on the RHS is mirrored but not marked on the LHS.
Whilst having a typically Septic 'guarding the six' appproach, the Cessna support folk are usually quite competent and helpful, as long as you're not pointing out some of the weaknesses of their designs or manuals.