This often comes down to how you protect your base station sites from lightning strikes. The broad theory for lighning protection is that you need to hold the entire site at the same potential such that when you have a strike on the tower, the entire site floats to the same potential to avoid damaging currents flowing through your equipment – with the path to ground remaining as far as possible outside of the hut via the direct tower earth grid. In order to hold the entire site at the same potential all earths need to be tied together otherwise you rin the risk of creating potential differences and potentially easier paths to ground for the lightning current via your equipment – which of course will destroy it if you suffer a strike.
Having said all that, sometimes Lightning just does wierd things and no amount of design will spare you from damage – but earthing in this way should generally help.
Note – this is just a broad guide – and individual site design may be quite different depending on how your total site earthing layout has been done so dont take this as correct in all cases.