Unplugging power cords from amps/ pre amps

Does the manufacturer specifically warn to unplug the power cord only at the receptacle and not at the equipment? 

Since the power cord detaches at the equipment, it is reasonable to assume that some end users would find it more convenient to plug/unplug at the equipment end. If that is a problem for some reason then a caution would be printed on the owners manual and the back of the equipment. Also, the equipment end is chamfered to fit the receptacle, preventing inadvertent polarity switching. All these signs point to it's okay to unplug everything from the equipment.

@OP There is no problem unplugging your equipment at the component end. Just  be absolutely sure to do it after turning off the relevant components.

The biggest risk in thunderstorms is to anything that's connected to an antenna like a radio aerial or satellite dish.

I have seen fires started by lightning strikes to such equipment.

I just blew out my Jeff Rowland Model 201 stereo amp power modules by plugging in the IEC into the amp when  the power cable was plugged in. 

Make sure the power is off to the power cable before plugging in the IEC to your amp. 

@soix Maybe I’ve just been lucky or have robust equipment, but all my stuff since five years ago runs through an Audience power conditioner and that’s enough to keep me from yanking power cords every time I hear thunder — just not gonna do that.

Has using a power conditioner improved your sound ? i.e. dirty power artifacts etc. Are you using audiophile AC cables to your components?

I am in a 110 apartment building built-in 2010. We have fiber optical Internet, but I don’t stream just yet, happy just playing records for now

I am using a SurgeX SEQ for sequencing and surge protection. I'm not sure how it affects the sound yet. but I don't worry about lightning as much now.