Robert, when I refer to Battery Tender Juniors and a Plus, I am talking about the brand name.
They are all float chargers with a brain. I won't even own a constant-run trickle charger (for the reasons you point out). My big car charger could be set to trickle constant, but I always use a timer on that one.
Jr

Plus (higher charge rate)(after this one burned out, I stuck with the Jrs, which have not burned out yet)

There are others just as good like Ctech, and at least one guy said his Battery Tender was messed up, but mine have been great, for years and years.
Finally I have worried about a fire. But I'm on a modern 200A service, all my outdoor circuits are GFCI, each tender is fused, and my bike is fused (all charging done on batteries installed in bikes with pigtails). No fire since 2005, so I feel pretty good about it.
BTW, on tires, I always have a spare front ready to go. But I run 37K mile Goodyears on back, and those tires age in the shed. So I never have backups for those. If I need one, I get it fresh. I need at least one front each year, and sometimes two. My last two Amazon Goodyears were at my door in a couple days.