They do seem to be fragile things. Only 1 out of the 3 units I have works reliably, and one of the failed ones is a replacement for a previously failed unit. They're not sending their best.
The unit it's built into is proper sturdy stuff which is why the 'shake to wake' function is a necessity - don't want the faff of taking it all apart to turn the tracer back on after a break.
@Lozart Between games. Between game days wouldn't bother me at all as it'd be what I'd do anyway but it's no good if it auto-offs after 5 mins and won't auto on.