I have two Platinum Power PP-1 high current balanced power conditioners and have never had a problem and I live in NM which has brief daily thunderstorms starting this time of year. I know my PP-1's have in-rush current protection that does just that on power-up in addition to the 20 amp mains magnetic circuit breaker on the unit of which I think the BPT also employs on their units.
I myself wouldn't be worried about any equipment damage from the BPT or any balanced power transformer unit.
I myself wouldn't be worried about any equipment damage from the BPT or any balanced power transformer unit.