Not sure what you mean? Wouldn't the double spender immediately tumble them by exchanging them for other coins across a bunch of different exchanges making a fork to fix it nigh impossible?
Most smallcaps have tiny volumes and aren't traded on many exchanges. Getting the coins into (and out of) an exchange isn't immediate. Even worse most of the volume is likely to be on a trustworthy exchange that does some basic KYC (and extended KYC for withdrawals). Basically, for most $1M cap coins, you'd be lucky to get $5k out if all goes well.
I mean, I guess it's still viable. It's just street-robbery-viable.
