Hi @Elaine617
There have been a few posts re this lately.
I also synch my calendars, but early on I learned that the synch often failed. I have IB so that would be disastrous for me.
I am not particularly tech saavy but I make sure I always have my phone with me. when I get an alert that I have a booking I manually block the dates on the other platforms - even when the synch IS working there is often a delay of 5 - 10 mins. It does not harm, when (if) the synch kicks in, I'm just double blocked instead of double booked.
I'm never inundated with bookings though, so for me it's no great hassle and I prefer the extra effort to ensure peace of mind...