Well you've just got to watch what you're doing BBS. Modern cars have such sensitive self diagnosis, mostly sensing changing in resistance and voltages that adding stuff into sytstems that weren't designed for it is always a risk that has to be calculated
Most vehicle fires are add ons that are improperly wired or fused
If a fuse is going on your cigarette lighter then you need to sort it and I would do that first because that's also your best line for somewhere to plug in or add extras. It's designed to run accessories so it's the safest place
Fuses go for a reason and you've already had a potential fire risk on your hands which is why it's blowing. Disconnect the cigar lighter connector and do some checks to find out the cause of your short circuit. It's most likely the cigar lighter itself but it depends if you've already done any mods to it, like piggy backs or add ons
You want everything that can possibly be off to be off when you pull the key out of the ignition. Otherwise, in the event of a short circuit you have an uncontrollable run away. Hard wiring into the radio head unit is a permanently live feed if you've selected radio to be on with ignition off so it's much more risky and the cabling is designed to take the radio and nothing else